Portobello Pot Roast (Vegetarian!)

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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, guys!

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!

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”.

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

  1. I’ve tried making this several times, and every time it comes out VERY different than the picture. (Doesn’t everything”)
    Our sauce seems so much thinner than what is pictured and everything comes out mushy when cooking exactly as the recipe suggests for the InstantPot. Tonight, I tried cooking at 14 minutes instead of 20, and it’s better but still mushy. I really don’t know what I’m doing wrong. I was really looking forward to this. Maybe I’m expecting too much of myself. The flavor is good, albeit a little bland. But overall, the dish is delish.

  2. This was delish! Made it last night (Instant Pot version) and was extremely hopeful that the results tasted as good as it looked. I was not disappointed in the least. Reheated it for lunch today. Definitely a 5-Star keeper even with me forgetting the wine, Worcestershire and tomato sauce and using “Better than Bouillion Organic Chicken Base” in lieu of vegetable stock. Next time, I’ll add missing ingredients as well as chopped bell peppers and celery sauteed along with the onions. Believe me, whatever you’d add to your pot roast can be added to this. You won’t be disappointed either nor will you miss the meat.

  3. Do you have nutrition information available?

  4. I see where the ingredients list says 6 cups vegetable broth divided…then only 2.5 cups added to the crock pot plus the other half cup to mix with cornstarch. When do you use the other 3 cups of vegetable stock? Am I missing something?

  5. Nutrition Facts
    Serving size: 1 cup
    Servings: 7
    Amount per serving
    Calories 90
    % Daily Value*
    Total Fat 1.1g 1%
    Saturated Fat 0.9g 5%
    Cholesterol 0mg 0%
    Sodium 338mg 15%
    Total Carbohydrate 17.6g 6%
    Dietary Fiber 2.6g 9%
    Total Sugars 4.9g
    Protein 3g
    Vitamin D 0mcg 0%
    Calcium 27mg 2%
    Iron 1mg 6%
    Potassium 626mg 13%

  6. Tried this out today for something warm and cozy. Made a few changes as ingredients were limited (especially during this crazy time). Used sliced fresh yellow onions, frozen sliced carrots, used dried basil and parsley, and instead of cornstarch I used unflavored pea protein powder. Which not only thickens it up but ups the protein. And served it with chickpea pasta. It was delicious!!

  7. Does this freeze well?

    • Hi. Potatoes don’t freeze very well. They become grainy and mealy when defrosted. I’ve tried a few times myself with bad results. You might want to decrease the recipe if you can’t finish it all in a week.
      I double checked on Google and they confirmed it.
      Stay healthy

  8. how much does all of this cost

  9. no tomato paste in the instant pot version?

  10. Fair recipe. The instant pot directions are missing when to add tomato paste, mushrooms should all be cut in half at least, keep potato pieces fairly large, add frozen peas once it’s cooked, and pressure should be released after 15 minutes of natural release to avoid mushiness.

  11. This was tasty! I made the instant pot version and it did turn out a bit soupy for me, but we used a slotted spoon and ate over brown rice and it was good. Next time I would probably use a bit less broth. The mushrooms were delicious, this is a great concept.

  12. I’ve been vegetarian for most of my life. I like to cook pot roast for my husband when the weather gets cold. I love the smell, especially in the winter. Who would have guessed that I can make a decent substitute we both can eat out of baby Bella mushrooms? Made it today in the crockpot, and followers the recipe with just a few minor changes- no big carrots, so used a bag of baby carrots, used baby potatoes, halved, two boxes of baby Bella’s, and a jar of pearl onions (my only mistake -next tome I will use fresh onion…the jarred version taste pickled and are not a good sub for the frozen or fresh that the recipe called for). The liquid broth /sauce with the garlic, tomato paste, Worcestershire sauce and red wine was sublime. It had a complex, “beefy” flavor that smelled and tasted delicious. We are ours over a quinoa rice blend. I will definitely make it again. Thank you for the recipe!

  13. I love this recipe. It is comforting and delicious on a cold day. I have found that 12 minutes in the IP is perfect and I needed a little more cornstarch to thicken up the 2-1/2 cups of broth I used. I did not use 3 cups. Our garden yielded so much zucchini I added that in as well. We have had this with crusty bread and over noodles and each way is great. Thank you for sharing this recipe.

  14. Overall taste is good but definitely a little bland. Am going to try adding red pepper flakes and maybe some cheese (because who doesn’t love cheese?) to add to the flavor. Probably will not make again though.

  15. Just not what l was expecting. It smelled hearty but tasted bitter
    I’d omit the wine if l were to make it again

  16. What could I sub for the wine?

  17. This is a very tasty fall stew. I added some fresh rosemary, 3 stalks of celery, frozen green beans and peas. Made 12 servings for 3 families for Meatless Monday. Full of flavor. Soul satisfying. Nirvana in a bowl.