Gimme Some Oven

Portobello Pot Roast (Vegetarian!)

This post may contain affiliate links. Please read my disclosure policy.

This Vegetarian Portobello Pot Roast recipe can be made easily in the slow cooker or Instant Pot (pressure cooker). And it’s SO hearty and comforting and delicious!

Vegetarian Portobello Pot Roast Recipe

As a Midwestern girl through and through, I’ve gotta admit, I will always love me a good pot roast. But hey, whoever said that had to include roast beef?

A few weeks ago, when I found myself with two leftover cartons of baby bella mushrooms in the fridge that needed to be used up stat, I decided to try swapping them in as the main ingredient in my traditional pot roast recipe. And lo and behold, they turned out to be a plant-based swap made in heaven. This vegetarian pot roast recipe was a total winner!

It’s still full of those classic savory flavors (and garlicky gravy) that we all love. It’s quick and easy to prep, and easy to make either on the stovetop or in the slow cooker or Instant Pot. It’s naturally vegetarian and vegan. And it’s totally, wonderfully delicious.

My kind of comfort food.

Mushrooms for this Vegetarian Portobello Pot Roast Recipe

To make the recipe, start by gathering lots of your starring ingredient — portobello mushrooms. You’re welcome to use full-size portobellos if you’d like. Or, you can be like me and just use a few cartons of baby bellas. Chop them up into bite-sized pieces…

Vegetarian Portobello Pot Roast Recipe Ingredients

…then combine them in a slow cooker or pressure cooker, along with some potatoes, carrots, pearl onions, garlic, and all of the ingredients for that classic savory gravy. Cook until the potatoes are nice and tender. Then for a final step, thicken that gravy up a notch…

How To Make Portobello Pot Roast (Vegetarian / Vegan / Gluten-Free)

…and voila! This delicious veggie-filled mushroom pot roast will be yours to serve and enjoy!

Vegetarian Portobello Pot Roast Recipe with noodles

I went old-school and served mine over some egg noodles, but some grains or rice would also work well here. I served mine up with this simple salad and some red wine, and the meal was perfection.

Vegetarian twist for the win!

clock clock iconcutlery cutlery iconflag flag iconfolder folder iconinstagram instagram iconpinterest pinterest iconfacebook facebook iconprint print iconsquares squares iconheart heart iconheart solid heart solid icon
Vegetarian Portobello Pot Roast Recipe

Vegetarian Portobello Pot Roast

  • Prep Time: 10 minutes
  • Cook Time: 240 minutes
  • Total Time: 250 minutes
  • Yield: 6 -8 servings 1x


This vegetarian Portobello Pot Roast recipe is quick and simple to prep, easy to cook in the Instant Pot or slow cooker, and it’s full of the classic savory flavors we all love!


  • 1.25 pounds Yukon gold potatoes, cut into bite-sized pieces
  • 1 pound baby bella mushrooms (if they are large, cut them in half)
  • 2 large carrots, peeled and cut into bite-sized pieces
  • 2 cups frozen pearl onions*
  • 4 cloves garlic, peeled and minced
  • 3 sprigs fresh thyme
  • 3 cups vegetable stock, divided
  • 1/2 cup dry red or white wine
  • 3 tablespoons tomato paste
  • 2 tablespoons vegetarian Worcestershire sauce*
  • 2 tablespoons cornstarch
  • Kosher salt and freshly-cracked black pepper
  • optional garnish: finely-chopped fresh parsley


Slow Cooker Method:

  1. Add potatoes, mushrooms, carrots, onions, garlic, thyme, 2.5 cups vegetable stock, wine, tomato paste and worcestershire together in the bowl of a crock pot, and gently toss to combine.  Cook on low for 6-8 hours, or on high for 3-4 hours, until the potatoes and carrots are tender.
  2. In a separate bowl, whisk together the remaining 1/2 cup vegetable stock and cornstarch until combined.  Add to the roast mixture, and gently toss to combine.  Continue to cook for 1-3 minutes, until the sauce thickens up a bit.
  3. Serve immediately, garnished with fresh parsley if desired.

Instant Pot Method:

  1. Add potatoes, mushrooms, carrots, onions, garlic, thyme, 2.5 cups vegetable stock, wine, tomato paste and worcestershire together in the bowl of a pressure cooker, and gently toss to combine.  Close lid securely and set vent to “Sealing”.
  2. Press “Manual”, then press “Pressure” until the light on “High Pressure” lights up, then adjust the up/down arrows until time reads 20 minutes.  Cook.  Then let the pressure release naturally, about 15 minutes.  Carefully turn the vent to “Venting”, just to release any extra pressure that might still be in there.  Remove the lid.
  3. In a separate bowl, whisk together the remaining 1/2 cup vegetable stock and cornstarch until combined.  Add to the roast mixture, and gently toss to combine.  Continue to cook for 1-3 minutes, until the sauce thickens up a bit.
  4. Serve immediately, garnished with fresh parsley if desired.


Onions: Feel free to sub in sliced white onions, if pearl onions are not available.

Worcestershire: If making this recipe vegetarian, be sure to use vegan Worcestershire sauce.

***Cook time listed above is for a slow cooker set on “high”.

Share this Post

Leave a Reply

Your email address will not be published. Required fields are marked *

Recipe rating 5 Stars 4 Stars 3 Stars 2 Stars 1 Star

104 comments on “Portobello Pot Roast (Vegetarian!)”

  1. This looks absolutely delicious…do you think it would work out to halve the recipe? Very small family, it would be too much for us.

  2. I can’t wait to try it out!

  3. WOW! This sounds so good! I’m going to have to try it. Friendly suggestion to those who may try this: Try to use NON-GMO corn starch.

    Thank you so much for sharing this.


  4. Oh yummm this looks DELICIOUS and I feel I won’t even miss the meat! My BF and I have been vegan/plant based diet since July and I am excited to try all the warm/cozy winter meals – this one is definitely going to be tried! YUM!

  5. As soon as this hit my email I started craving it. Had it for dinner tonight and it was sooo good! My husband had 3 bowls. Can’t wait for my lunch leftovers tomorrow

  6. Made this tonight (added beef for my carnivorous hubby) but it was absolutely delish! Over the weekend I made your slow cooker chili and the coconut oil pumpkin bread, everything was amazing!
    Thank you for creating recipes with easy to get ingredients, easy to follow instructions and wonderful results!

  7. Hey! I made a half batch of this in the Instant Pot, and my carnivore husband was in heaven! I used the saute function when I added the cornstarch and broth and the sauce bubbled and thickened beautifully.

    Just wanted to suggest that you note that traditional Worcestershire sauce is not vegetarian or vegan as it contains anchovies. Your veggie readers like me would know that – and there are vegetarian Worcestershires available – but I could see a well-intentioned omnivore making this to serve to others without knowing that.

  8. Delicious & I didn’t miss the meat at all! I did transfer to a pan and thickened on the stove top.

  9. This sounds great and I just happen to have two packages of baby bella mushrooms in my fridge right now, so I will be making this tonight. Just curious, do you prefer using red or white wine in this??

  10. It was wonderful! Made it for meatless Monday and I will definitely make it again. Appreciate the Insta Pot instructions, thank you!

  11. Really good flavor but mine came out so soupy and nothing like the pictures! What did I do wrong?! I want to get that nice glaze on the veggies like you have in the pictures

    • Mine too! Taste was great but liquid never thickened. Followed instant pot directions.

  12. Quick question…how would I cook this on the stove?

    Thanks! :)

  13. Hi, I love your blog! I wanted to know if there was a substitute for the wine in this recipe? I don’t cook with it for religious purposes. Your feedback would be appreciated.

  14. Listen girl, can I just say, as a fellow food blogger, you have mastered taking pretty pictures with food in a crock pot. MASTERED. Finally, I can see that I need to slay down a white background to make it pop. thank you!!!

  15. This is Delicious! Don’t miss the meat at all. Used baby carrots.

  16. My wife made this tonight and it was delicious. I do wish the portion size and calories were included for us that are counting calories.

  17. Making this right now! Wondering if it freezes well??

  18. This is delicious! I added frozen peas at the end and heated until they thawed. The first time, I served it over noodles; the second, over polenta that I had pan fried. Both ways we’re great. Love this dish!

  19. What size crock pot can you use? I have a small (3.5qt) pot

  20. I just made this and it was so good! My grocery store was out of baby bellas so I had to use sliced. Otherwise I followed the Instant Pot instructions exactly. Mine came out pretty soupy but I think it may have been because of the sliced mushrooms. Next time I would do maybe 1.5 or double the mushrooms. We served this over a wild rice blend and between the two of us my boyfriend and I ate about half the recipe! I’m vegetarian and he’s not and we both loved it!

  21. Followed instructions EXACTLY. Turned out very bland and watery. Would not recommend at all. Very disappointed.

  22. Definitely good for something different. I did feel like a missed the meat a tad bit. Might make it again using a small amount of beef and a little less liquid. I subbed broth for the wine since I have young kids.

    As one of the posters suggested, I did hit the saute button on my instant pot to help thicken it. It was a little soupy. My veggies were cut small and a little overcooked so I also might cook a little less next time.

    Thanks for sharing.

  23. OMG this is incredible. Even my 15 year old non-vegan was asking for more. Hearty and delicious! Make some great bread, ad something green like a salad and you are in business! Will definitely make this again and again1

  24. Made this last night. We are omnivores – We LOVED this meal. Definitely a do again in our household

  25. I had the same experience as a few others, the sauce turned out thin. I added about 1/3 cup of nutritional yeast which thickened it right up

  26. I just cooked on stove top for about 2 hours. Got rave reviews. I didn’t have worchestersire sauce but used Pick-a-Pepper.

    • I made this in a slow cooker. It came out very soupy and just tasted bitter and not savory. I won’t make this again.

  27. I am new to vegetarian and finding replacements for those favorite comfort foods has been a challenge. Thistle recipe was spot on, thick gravy, plenty of veggies, very filling. Made in instant o, so simple. This will for sure go into the rotations.

  28. What can I use as a substitution for the Worcestershire sauce?

  29. Very easy to make. My guests and I loved it. Amazing flavor!

  30. I made this dish for a meal train. I used vegan creamy vegetable stock instead of regular vegetable stock, fresh pearl onions instead of frozen and I added a little more garlic. The flavor was really good and the vegetables were perfectly cooked. I will make it again for my family with a few changes. I would NOT use the vegan creamy vegetable stock again because the appearance of the sauce was so unappetizing. Also, I would increase the amount of mushrooms to 1.5 or 2 pounds. Here is what I did to thicken up the sauce: I placed the 1/2 cup stock and corn starch in a medium/small sauce pan (do not turn on). Once the InstaPot was vented, I poured the liquid from the InstaPot into the sauce pan. Turned on the burner under the saucepan and heated it until it reached my desired thickness (stirring constantly). Then, I poured it back over the vegetables. Yummy!

  31. Absolutely loved this recipe. Making it again but have added soaked, dried shitake mushrooms and some beautiful oyster mushrooms for some added texture and extra umami. Thanks

  32. I don’t use alcohol. Any substitution suggestions?

  33. I made this and it was outstanding! Only changes: I had no wine, and subbed the pearl onions with one sliced Vidalia onion (which was divine, all melty and carmelized). I also added some seitan for heft, too. So easy and scrumptious. Served with foccacia. Plenty of leftovers for the week. Thank you for the easy keeper!

  34. Made this tonight and it turned out AMAZING! Did it in the Instapot – followed the instructions, but also took some of the suggestions of others to put on “saute” for the last part and it thickened right up. Delicious. It’s going in my family’s recipe rotation for sure!

  35. Recipe is perfect! However, I did substitute 1.25 pounds of peeled and diced rutabagas and turnips for the potatoes since I do not eat potatoes. I also added some chopped celery. Skipped the wine and Worcestershire sauce but used low sodium veggie broth and it was perfect. Thank you for a great recipe.

  36. I just made this using an Instant Pot pressure cooker for the 1st time. Delicious.
    I’d like to do it again to see what may change. Consistency wise. Perhaps I won’t need to reduce next time.
    This time around, I chose to transfer the finished product to a pot on the stove to simmer out some liquid. I wanted to thicken it without more cornstarch. Just my preference. This is when I added pepper and salt. I have to get more comfortable with the pressure cooker.
    It was so incredibly good. I know this because my husband went for seconds! He’s not a huge eater and he’s a chef. So I had the biggest internal smile! Thanks!

    I plated mine over red mashed potatoes. Disclaimer: We add A LOT of butter to our mash, so when the “Pot roast” gravy melted into the butter….heaven.
    This is definitely a keeper recipe!!

    And, to anyone who needs to cut the recipe down, we like to cook extra and batch out some to freeze for quicky meals. This is a perfect recipe to freeze.

  37. Delicious! even with some accidental changes! i didn’t have wine or corn starch, so i skipped the wine and used a little flour. was delicious out of the pot, BUT i have an addiction to white pepper so i added a little and it was just the thing for me. excited to try prior reviewer’s suggestion for rutabaga and turnip, may also replace carrot with parsnip and see how that goes. great recipe that seems to have great flexibility! thank you!

  38. I liked the taste, but it did not thicken into a gravy. I used the instant pot version (which doesn’t have the tomato paste listed for some reason? I did add the paste as per the slow cooker instructions). I ended up adding a third tablespoon of cornstarch and still couldn’t get any thickening. I told my kids it was a soup :)

  39. This was really good. Even my meat eating husband agrees. At first I was not sure but by the time I was done I was soaking up all the juice with bread!! So good!

  40. This was absolutely amazing! Perfect vegetarian comfort food!

  41. Made this overnight in my slow cooker and OMG. So delicious. I used Bisto Gravy Granules (Vegetarian friendly beef flavor) to thicken this up instead of cornstarch as it adds that extra beefy kick. They are a little pricey as they are imported from the UK but they are so worth it! 10/10 I’m obsessed with this recipe!!

  42. I just tried making this. The directions for InstantPot dont call for the tomato paste or corn starch. I used the tomato paste but didn’t use the corn starch. It came out pretty watery, not nearly as saucy like the picture. It was more soup like. What did I do wrong?

  43. 5 stars with the following boosts:
    – Thoroughly browned the first half of the mushrooms in a splash of olive oil over medium high heat, cut side down without stirring in my pressure cooker on the stovetop while I chopped up everything else. I also added half a cube of mushroom boullion.
    – Added about a tsp of chopped dried porcini mushrooms to the wet mix before closing the pressure cooker. used red wine, not white.
    – Added a splash of soy sauce
    – Finished it with a splash of red wine vinegar
    – Served with buttered spatezli, tossed with parsley

  44. I made this tonight and it turned out ok. I had to make a Rue to get a gravy because it was soupy. I used 3TBS butter to 3Tbs flour and added broth from the pot. I wish I would have omitted the tomato paste it wasn’t necessary and it added an odd flavor. I will try again with a few changes.

  45. Mmm this was so good. Easy too. I did what others suggested and let it thicken in the instant pot on simmer for about 5-6 minutes. Thought it needed a bit more dimension to the broth so I added salt, pepper, and rosemary and garlic powder. Will totally remake. Served it alone with crusty bread and a glass of red wine!

  46. This is the first recipe I’ve tried in my new pot. It was very simple to follow and turned out really tasty. However, mine is rather “soupy” like other reviewers mentioned. Since I had planned to serve this over noodles, I don’t mind the extra liquid. Next time, I’ll either add more potatoes or less liquid. Either way, I’m sure it will taste good.

  47. My 15 yr/old daughter is the vegetarian in a house of carnivores. This meal I made double, both meat and mushrooms. I cannot believe the flavor so rich and yummy. She barley had enough to take for school lunch tomorrow. Simple and easy Crock-Pot meals for our family are the best, and this meal has made it in our fall/winter rotation. We can’t wait to try other recipes ?

  48. I found this recipe too sweet for our liking. I may play around with the ingredients to get it to be less sweet.

  49. I loved this recipe but need to try it again. After reading the reviews I will sauté it to thicken it up. BUT my sauce came out watery but also had a acidity/vinegary taste, did anyone else’s? Don’t know what I did wrong. Followed the instant pot step by step, since the tomato paste was listened I still added it & I used more mushrooms then listed.

  50. Really enjoyed the flavor of this recipe. Can never get enough of portobello mushrooms.
    To make it less watery when using Instant Pot reduce stock to two cups. Almost no liquid is lost when pressure cooking. (The mushrooms are mostly water.) Substitute BRAGG Liquid Aminos for the Worcestershire sauce.