Blueberry Oatmeal Crumble Bars

Blueberry Oatmeal Crumble Bars strike the perfect balance between comfort food and elegant dessert. With a buttery oat crust and topping sandwiching a bright, jammy blueberry filling, these bars are equal parts rustic and refined. Whether you’re making them for a brunch, picnic, or as a sweet snack with coffee, these bars deliver a crave-worthy blend of textures and flavors.

The base and crumble topping come together in one bowl, using rolled oats, brown sugar, flour, and butter to create a crisp yet tender bite. The filling is simple—fresh blueberries tossed with sugar, lemon juice, and cornstarch—allowing the fruit’s natural flavor to shine. As they bake, the blueberries soften into a luscious, slightly tart layer that contrasts beautifully with the buttery oat layers.

These bars are especially wonderful because they’re versatile and sturdy—perfect for slicing, storing, and transporting. They can be served slightly warm with a scoop of vanilla ice cream, chilled from the fridge, or even packed into lunchboxes. Whether you’re after an easy bake for a gathering or just looking to use up a pint of blueberries, these crumble bars are a timeless, satisfying choice.

Why You’ll Love This Recipe

1. Buttery, crumbly texture with a juicy fruit center

The oat crust and crumble are soft yet crisp, while the blueberry layer stays moist and flavorful.

2. Easy, one-bowl dough for crust and topping

Save time and dishes by mixing one batch for both the base and crumble.

3. Seasonal or year-round baking

Great with fresh summer blueberries but works beautifully with frozen berries too.

4. Great for breakfast or dessert

Perfectly sweet and hearty for brunch, yet indulgent enough for an after-dinner treat.

5. Stores and travels well

These bars keep their shape and flavor, making them ideal for meal prep or gifting.

Ingredients

Crust and Topping

• All-purpose flour
• Rolled oats
• Light brown sugar
• Granulated sugar
• Baking powder
• Salt
• Unsalted butter (softened, but still cool)
• Pure vanilla extract

Blueberry Filling

• Fresh blueberries
• Granulated sugar
• Cornstarch
• Lemon juice

Variations

• Frozen Blueberries: Substitute frozen blueberries (no need to thaw) if fresh aren’t available.
• Add Spices: Mix a bit of cinnamon or cardamom into the crumble for extra warmth.
• Mixed Berries: Use a blend of raspberries and blueberries for a more complex filling.
• Lemon Zest: Add a teaspoon of lemon zest to the filling for a zesty twist.
• Vegan Option: Use vegan butter and ensure your sugar is plant-based certified.

How to Make the Recipe

Step 1

Preheat your oven and line an 8×8 or 9×9-inch baking pan with parchment paper, leaving some overhang for easy removal.

Step 2

In a large bowl, combine the flour, rolled oats, brown sugar, granulated sugar, baking powder, and salt.

Step 3

Add the butter and vanilla extract. Mix with a pastry cutter or your hands until the mixture resembles coarse crumbs and begins to hold together.

Step 4

Press about two-thirds of the mixture into the bottom of the prepared pan to form the crust. Set aside the remaining mixture for the topping.

Step 5

In a medium bowl, toss the blueberries with granulated sugar, cornstarch, and lemon juice until evenly coated.

Step 6

Spread the blueberry mixture evenly over the crust layer in the pan.

Step 7

Sprinkle the remaining crumble mixture over the top of the blueberries, pressing gently to adhere.

Step 8

Bake until the topping is golden brown and the blueberry filling is bubbling, about 35–40 minutes. Let cool completely before slicing.

Tips for Making the Recipe

• For clean cuts, chill the bars before slicing with a sharp knife.
• Don’t overmix the crumble; you want a crumbly, rustic texture.
• Use parchment paper for easy lifting and less mess.
• If using frozen berries, add 1 extra teaspoon of cornstarch.
• Store at room temperature for a day or refrigerate for longer freshness.

How to Serve

Serve these bars slightly warm with whipped cream or ice cream for dessert. For breakfast, enjoy them cold with coffee or tea. They’re also perfect for potlucks, bake sales, or as a quick grab-and-go snack.

Make Ahead and Storage

Storing Leftovers

Store in an airtight container at room temperature for up to 2 days or in the refrigerator for up to 5 days.

Freezing

Freeze cooled bars individually or in layers with parchment in between. Store in a freezer-safe container for up to 2 months. Thaw in the refrigerator or at room temperature.

Reheating

Warm briefly in the microwave or a 300°F oven for a few minutes if you want to refresh the texture.

FAQs

1. Can I use quick oats instead of rolled oats?

Rolled oats are preferred for texture, but quick oats can work in a pinch—they’ll result in a softer, less textured crumble.

2. Can I double the recipe?

Yes, double the ingredients and bake in a 9×13-inch pan. You may need to increase baking time slightly.

3. Are frozen blueberries okay?

Yes, but don’t thaw them and increase cornstarch to prevent excess moisture.

4. What’s the best way to cut them cleanly?

Chill the bars and use a sharp, clean knife. Wipe between cuts for neat edges.

5. Can I reduce the sugar?

Yes, reduce both sugars in the crust by 2 tablespoons each without major texture loss.

6. Is the lemon juice necessary?

Yes, it balances the sweetness and enhances the blueberry flavor.

7. Can I make this gluten-free?

Use a gluten-free flour blend and certified gluten-free oats.

8. What kind of butter should I use?

Unsalted butter is best so you can control the salt content.

9. Can I add nuts to the topping?

Yes, chopped almonds or pecans add crunch and richness.

10. Are these bars good for breakfast?

Absolutely. They’re hearty, fruity, and just sweet enough to enjoy with your morning coffee.

Conclusion

Blueberry Oatmeal Crumble Bars are a delightful, versatile treat that work just as well for breakfast as they do for dessert. With a golden oat crumble and a fresh, vibrant berry filling, they offer the perfect mix of sweetness, texture, and flavor. Easy to make and even easier to love, these bars are sure to become a staple in your kitchen for all seasons.

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