These Blueberry Oat Crumble Bars are little squares of summer heaven bursting with sweet, juicy blueberries and nestled between a buttery crust and an oatmeal crumble topping. All the flavor of a fresh blueberry pie with half of the effort!
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Summer is filled with sunshine, warm breezes, and of course, freshly picked blueberries. But baking a whole pie can feel intimidating. If you're craving that sweet and juicy blueberry taste in a simpler form, then look no further than these incredible Blueberry Oat Crumble Bars.
These blueberry bars are perfect for anyone who wants a delicous treat without the commitment of a full pie. They're easier to make, easier to share, and trust me, just as delicious.
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Why you'll love these blueberry pie bars
➤ Quick and easy: The oat crumble mixture forms pulls double duty as both the crust and the topping - no pastry crust to roll! Plus the whole recipe comes together in about an hour.
➤ Simple ingredients: You likely have most of the staples on hand already – flour, oats, butter, sugar, and of course, blueberries!
➤ Family-friendly: These bars are a guaranteed crowd-pleaser, loved by kids and adults alike. Plus, they're portable for picnics or potlucks.
Ingredients and Substitutions
Compared to pie, these blueberry oatmeal bars are a breeze to pull together. No fancy equipment or crust rolling required.
A few ingredient notes:
Blueberries: It's hard to go wrong with fresh blueberries in the summer, but if you're craving blueberry pie bars out of season, frozen berries work just as well in this recipe.
Old-fashioned oats: Quick oats can be used in a pinch, but they will absorb more moisture and create a softer crumble. Opt for rolled oats (also called old-fashioned oats) for the best texture. You can also swap some of the oats for chopped nuts or seeds in the crumble for a bit of crunch.
Lemon juice and zest: Blueberries and lemon are a match made in heaven, but if you don't have a lemon handy, you can use a lime instead. It will give it a similar brightness and hint of citrus flavor as a lemon.
Butter: For a vegan option, use melted vegan butter or coconut oil.
Instructions
This blueberry crumble bar recipe is quickly made by hand.
Stir together some flour, oats, sugars, cinnamon and baking powder. Add the melted butter and vanilla and stir until incorporated. Reserve ⅓ of the oat mixture and press the remaining into an 8" pan lined with parchment paper. Bake for 10 minutes.
While the crust is baking, stir together the blueberries, lemon juice and zest, sugar and cornstarch in a small saucepan. Heat over medium heat until the sugar is melted and the juices coat the back of a spoon, about 3 minutes.
Pour the blueberry mixture into the crust. Top with reserved oat crumble mixture. Bake for 35-45 minutes or until golden brown and bubbling on the sides.
Tips for the BEST Blueberry Oat Crumble Bars
✘ Lightly spray the baking pan before adding your parchment paper to help it stay in place easily.
✘ Need a gluten-free blueberry oat bar? Substitute the rolled oats with gluten-free oats and the all-purpose flour with a gluten-free flour blend (such as King Arthur Measure for Measure Gluten-Free Flour or Bob's Red Mill 1 to 1 Gluten-Free Baking Flour).
✘ Zest the lemon before squeezing it for the juice needed in this recipe.
✘ These bars will keep in the fridge for up to three days and in the freezer for up to three months. If freezing, layer the bars between sheets of parchment paper.
✘ Serving a crowd? You can double this recipe to make a 9x13" pan. The bars will be a little thicker and take a few minutes longer to bake.
✘ Let Them Cool Completely: These bars are best enjoyed at room temperature, so be sure to let them cool completely before slicing. This allows the filling to set properly.
More Easy Summer Desserts
Fresh produce makes summer desserts extra flavorful!
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Recipe
Blueberry Oat Crumble Bars
Ingredients
- 1¼ cups all-purpose flour
- 1 cup rolled oats
- ⅓ cup granulated sugar
- ⅓ cup brown sugar, packed
- 1 teaspoon baking powder
- ½ teaspoon ground cinnamon
- ½ teaspoon vanilla extract
- 8 tablespoons unsalted butter, melted
- 3½ cups blueberries
- zest of 1 lemon
- 1 tablespoon fresh lemon juice
- ¼ cup granulated sugar
- 1 tablespoon cornstarch
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Instructions
To make the crumble:
- Preheat oven to 350°F. Line an 8x8" square baking pan with enough parchment paper that so it hangs over the sides. (You'll use it as handles to lift the bars out of the pan later.)
- Stir together flour, oats, ⅓ cup granulated sugar, brown sugar, baking powder and cinnamon in a bowl. Stir in vanilla and butter. Reserve ⅓ of mixture (about 1 cup) in a small bowl and refrigerate. Press remaining mixture into bottom of prepared baking pan. Bake for 10 minutes. Set aside to cool slightly.1¼ cups all-purpose flour, 1 cup rolled oats, ⅓ cup granulated sugar, ⅓ cup brown sugar,, 1 teaspoon baking powder, ½ teaspoon ground cinnamon, ½ teaspoon vanilla extract, 8 tablespoons unsalted butter,
- While the crust is baking, add blueberries, lemon zest, lemon juice, ¼ cup granulated sugar and cornstarch to a small saucepan. Heat over medium heat and stir together until sugar is melted. Continue to cook for about 3 minutes or until the blueberry juices coat the back of a spoon.3½ cups blueberries, zest of 1 lemon, 1 tablespoon fresh lemon juice, ¼ cup granulated sugar, 1 tablespoon cornstarch
- Pour warm blueberry mixture into crust. Sprinkle with remaining oatmeal mixture from refrigerator. Bake for 35-45 minutes or until the edges bubble and the top is golden brown. Cool completely.
- When ready to serve, lift bars from the pan using parchment paper. Place on a cutting board and cut into 16 pieces.
Notes
- Fresh or frozen blueberries work equally well in this recipe.
- Use old-fashioned or rolled oats for the best results. Quick oats can be used in a pinch but the crumble will be softer. You can also swap in some chopped nuts or seeds for oats in the crumb mixture for extra crunch.
- Don't forget to zest the lemon before juicing it! (It's really hard to zest a squeezed lemon, speaking from personal experience.)
- Serving gluten-free guests? Swap out the all-purpose flour and rolled oats for gluten-free flour blend and gluten-free rolled oats.
- Lightly spray the baking pan before adding your parchment paper to help it stay in place easily.
- Let the bars cool completely before slicing. This allows the filling to fully set.
- These bars will keep in the fridge for up to 3 days and in the freezer for up to three months. If freezing, layer the bars between sheets of parchment paper.
- Serving a crowd? You can double this recipe to make a 9x13" pan. The bars will be a little thicker and take a few minutes longer to bake.
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Nutrition
Nutrition info not guaranteed to be accurate.
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