Blueberry Oatmeal Crumble Bars: An Easy and Delicious Recipe!

Blueberry oatmeal crumble bars are the perfect treat for any time of day.

With a buttery crust, a juicy blueberry filling, and a crunchy oat topping, they’re satisfying and versatile.

Enjoy them as a quick breakfast, a sweet snack, or a comforting dessert.

Made with wholesome ingredients like old-fashioned oats and fresh blueberries, this recipe strikes the perfect balance between indulgence and nutrition.

Here’s how to make them at home!

How to Make Blueberry Oatmeal Crumble Bars: At A Glance

1. Preheat oven to 350°F (175°C) and line an 8×8-inch pan with parchment paper.
2. Mix flour, oats, sugars, cinnamon, salt, butter, and egg yolk for the crust and crumble.
3. Press two-thirds of the mixture into the pan to form the crust.
4. Toss blueberries with lemon juice, sugar, and cornstarch for the filling.
5. Spread blueberry filling over the crust and top with reserved crumble mixture.
6. Bake for 45-55 minutes until golden and bubbling.
7. Cool completely for at least 3 hours before slicing.

Why You’ll Love This Recipe

A Perfect Balance of Textures and Flavors

This recipe delivers a delightful combination of textures and flavors.

The buttery crust provides a firm yet tender base.

The juicy blueberry filling bursts with natural sweetness, enhanced by a hint of lemon.

On top, the crunchy oat crumble adds a satisfying contrast to the soft filling.

Simplified Preparation

One of the best parts of this recipe is its simplicity.

The same oatmeal mixture is used for both the crust and the crumble topping.

This eliminates the need for extra steps, making the process quicker and more straightforward.

With just one bowl and a handful of ingredients, you can create a dessert that looks and tastes impressive.

Versatile Blueberry Options

This recipe is adaptable to what you have on hand.

You can use fresh blueberries for a quick bake or frozen ones if that’s what’s available.

There’s no need to thaw frozen berries, though the bake time may be slightly longer.

Either way, the result is a luscious, fruity filling that pairs beautifully with the oat layers.

A Treat for Any Occasion

Whether you’re serving these bars at breakfast, as a midday snack, or as a dessert, they always fit the moment.

Their wholesome ingredients make them feel light enough for the morning, while their richness makes them indulgent enough for dessert.

These bars truly check all the boxes for a versatile, crowd-pleasing treat.

Ingredients Overview

A great recipe starts with quality ingredients.

Here’s what you’ll need to make these delicious blueberry oatmeal crumble bars.

For the Crust and Topping

• 1 cup (125g) all-purpose flour: Provides structure and a slight chewiness for the crust and crumble.
• 3/4 cup (75g) old-fashioned rolled oats: Adds texture and heartiness to the layers. Avoid quick or instant oats for best results.
• 1/2 cup (100g) granulated sugar: Sweetens the crust and crumble topping, balancing the tartness of the blueberries.
• 1/4 cup (50g) packed brown sugar: Adds a rich, molasses-like sweetness that complements the oats and cinnamon.
• 1/2 teaspoon ground cinnamon: A hint of warmth to enhance the crumble’s flavor.
• 1/4 teaspoon salt: Balances the sweetness and rounds out the flavors.
• 1/2 cup (113g) unsalted butter, melted: Binds the crust and topping while adding a rich, buttery taste.
• 1 large egg yolk: Helps hold the crust together, ensuring it’s firm but tender.

For the Blueberry Filling

• 2 cups (300g) blueberries (fresh or frozen): The juicy star of the recipe. Use fresh for a quicker bake or frozen for convenience.
• 1 tablespoon freshly squeezed lemon juice: Adds brightness and enhances the blueberry flavor.
• 1/4 cup (50g) granulated sugar: Sweetens the filling without overpowering the natural fruitiness.
• 2 teaspoons cornstarch: Thickens the filling, ensuring it holds together for neat slices.

Step-by-Step Instructions

Step 1: Preparation

• Preheat your oven to 350°F (175°C). This ensures the oven is at the perfect temperature when your bars go in, helping them bake evenly.
• Line an 8×8 inch baking pan with parchment paper. Leave some overhang on the sides to make removing the bars easier later. This step also helps prevent sticking.

Step 2: Making the Crust and Topping

• In a medium mixing bowl, combine the dry ingredients:
  • 1 cup all-purpose flour
  • 3/4 cup old-fashioned oats
  • 1/2 cup granulated sugar
  • 1/4 cup packed brown sugar
  • 1/2 teaspoon ground cinnamon
  • 1/4 teaspoon salt
  Stir everything together until evenly distributed.
• Add the wet ingredients:
  • Pour in 1/2 cup melted unsalted butter and mix thoroughly.
  • Add 1 egg yolk and stir until the mixture becomes crumbly.
• Reserve about 1 cup of this mixture for the crumble topping. Set it aside in a small bowl.
• Press the remaining mixture into the prepared pan to form the crust. Use your hands or the back of a spoon to press it down firmly and evenly.

Step 3: Preparing the Blueberry Filling

• In a separate bowl, prepare the filling:
  • Combine 2 cups of blueberries (fresh or frozen), 1 tablespoon lemon juice, 1/4 cup granulated sugar, and 2 teaspoons cornstarch.
• Stir until the blueberries are well coated. The sugar and cornstarch will help thicken the filling as it bakes, while the lemon juice enhances the flavor.

Step 4: Assembling the Bars

• Spread the blueberry mixture evenly over the crust. Make sure the blueberries are distributed in a single layer for even baking.
• Sprinkle the reserved crumble mixture over the blueberries. Squeeze the crumble mixture in your hand to create small clusters before sprinkling it for a more textured topping.

Step 5: Baking

• Bake the bars in the preheated oven for 45-55 minutes. The bars are ready when the topping is golden brown and the blueberries are bubbling.
• If using frozen blueberries, you may need to bake for a few extra minutes.

Step 6: Cooling and Serving

• Allow the bars to cool completely in the pan for at least 3 hours. This cooling period is crucial to ensure the bars set properly and slice cleanly.
• Use the parchment paper overhang to lift the bars out of the pan. Place them on a cutting board and slice into squares or rectangles.
• Serve at room temperature or warmed up. For a special treat, pair the bars with a scoop of vanilla ice cream.

Nutritional Information

• Calories: 191
• Total Fat: 9g
• Saturated Fat: 5g
• Cholesterol: 30mg
• Sodium: 60mg
• Total Carbohydrates: 27g
  • Dietary Fiber: 2g
  • Sugars: 15g
• Protein: 2g

Tips for Success

Use the Right Oats

Stick to old-fashioned rolled oats for the crust and topping.

Quick or instant oats won’t work well in this recipe.

They break down too much during mixing and baking, losing their texture and making the bars overly soft.

Rolled oats provide the perfect chewy consistency and a rustic look.

Enhance the Flavor with Lemon Zest

For an extra burst of brightness, consider adding 1-2 teaspoons of lemon zest to the blueberry filling.

The zest intensifies the citrus flavor and complements the sweetness of the blueberries.

This small addition can make a noticeable difference in the overall taste.

Cool Completely Before Cutting

Patience is key when slicing these bars. Allow them to cool thoroughly in the pan for at least 3 hours before cutting.

Cooling gives the blueberry filling time to set and prevents it from spilling out when sliced.

If you’re in a hurry, place the pan in the fridge to speed up the process.

Proper cooling ensures clean, sharp edges and a professional finish.

Variations and Substitutions

Try Different Berries

While blueberries are the star of this recipe, you can easily swap them for other berries.

Raspberries or blackberries work just as well and bring their own unique flavors.

For a mix of flavors, try combining different berries like strawberries and blueberries or a medley of your favorites.

Just be mindful that some berries, like raspberries, can be juicier and may require a bit more cornstarch to thicken the filling.

Make It Gluten-Free

This recipe can be adapted for a gluten-free diet with a few simple changes.

Replace the all-purpose flour with a gluten-free flour blend.

Ensure the blend is suitable for baking and contains xanthan gum if possible.

Also, use certified gluten-free oats to ensure no cross-contamination.

Reduce the Sugar

If you prefer a less sweet version, you can reduce the sugar in both the crust and the filling.

For the crust, use 1/3 cup of granulated sugar instead of 1/2 cup and 2 tablespoons of brown sugar instead of 1/4 cup.

In the filling, decrease the granulated sugar to 2 tablespoons.

Storage and Freezing Instructions

To keep your blueberry oatmeal crumble bars fresh and delicious, proper storage is essential.

If you plan to enjoy them within a couple of days, you can store the bars at room temperature in an airtight container for up to 4 days.

For longer storage, place the bars in the refrigerator where they will stay fresh for up to 1 week.

If you want to store them for an extended period, freezing is a great option.

Wrap individual bars tightly in plastic wrap and place them in a freezer-safe container or bag.

They will keep well in the freezer for up to 3 months.

When you’re ready to enjoy frozen bars, thaw them in the refrigerator overnight to maintain their texture and flavor.

Reheating them briefly in the oven or microwave can restore their freshly baked feel if desired.

Conclusion

Blueberry oatmeal crumble bars are simple to make, versatile, and packed with flavor.

Whether you enjoy them as a snack, dessert, or breakfast, they’re sure to be a hit.

Give this recipe a try and share your experience in the comments.

We’d love to hear your feedback and any creative variations you’ve tried!

FAQs

Can frozen blueberries be used without thawing?

Yes, frozen blueberries can be used without thawing.

Simply add them directly to the filling mixture and bake as instructed.

Keep in mind that frozen berries may release more liquid during baking, so you might need to bake the bars a few minutes longer to ensure the filling sets properly.

How can I prevent the crust from becoming soggy?

To prevent a soggy crust, make sure the blueberry filling is evenly coated with cornstarch before spreading it over the base.

The cornstarch helps thicken the filling as it bakes, reducing excess moisture.

Additionally, press the crust mixture firmly into the pan to create a solid base that holds up well to the filling.

Is it possible to double the recipe for a larger batch?

Yes, you can double the recipe to make a larger batch.

Use a 9×13-inch pan instead of an 8×8-inch pan, and follow the same preparation and baking steps.

The baking time should remain similar, but check for doneness by ensuring the crumble topping is golden brown and the blueberry filling is bubbling.