This Blueberry Crumble Bars recipe is quick and easy to make, and filled with the most irresistible sweet blueberry filling. Perfect for fresh berries in the summertime, or frozen berries year-round.
- 1 pound (about 4 cups) fresh or frozen blueberries
- ¼ cup brown sugar, tightly-packed
- ¼ cup lemon juice
- 1 ½ tablespoons cornstarch
- 2 ¼ cups old-fashioned oats
- 1 ½ cups all-purpose flour
- ½ cup brown sugar, packed
- ½ teaspoon ground cinnamon
- ½ teaspoon salt
- 1 cup (2 sticks) melted butter
- Preheat oven to 350°F. Line an 8×8- or 9×9-inch square baking dish with parchment paper; set aside.
- In a large saucepan, stir together the blueberries, brown sugar, lemon juice and cornstarch until combined. Heat over medium heat until the blueberries reach a simmer, stirring occasionally. Then reduce heat to medium-low and simmer for 10 minutes, stirring and mashing a few of the blueberries occasionally, until the mixture is thickened. Remove from heat and set aside.
- Meanwhile as the berries are cooking, whisk together the oats, flour, brown sugar, cinnamon and salt until combined. Drizzle the melted butter evenly over the mixture, then stir until completely combined.
- Transfer half of the filling to the prepared pan, and press it evenly into the bottom of the pan to form the bottom layer of the bars. Pour the blueberry mixture on top, and spread it around evenly. Then use your fingers to crumble and evenly sprinkle the remaining oatmeal mixture on top of the blueberry layer.
- Bake for 30-35 minutes, or until the blueberries are bubbling around the edges. Transfer to a cooling rack and cool until the bars reach room temperature. Then cover and refrigerate until completely chilled.
- Cut and serve chilled. Or store in the refrigerator for up to 4 days.