Blueberry Oatmeal Crumble Bars are everything you could want in a homemade dessert: simple to make, packed with juicy fruit, and finished with a golden, buttery crumble. These bars strike the perfect balance between sweet and tart, chewy and crisp. Made with wholesome ingredients like rolled oats, oat flour, maple syrup, and fresh or frozen blueberries, they’re naturally gluten-free and easy to adapt for dairy-free diets as well.

Perfect as a snack, dessert, or even a breakfast on-the-go, these bars are a delicious way to enjoy seasonal berries. The oat-filled crust and topping offer a warm, nutty base, while the blueberry filling becomes bubbly and jam-like as it bakes. Add a touch of almond extract and a hint of lemon zest for extra brightness, and you’ve got a treat that’s hard to resist.

Whether you’re baking for a special occasion or simply looking to use up extra blueberries, these crumble bars are an ideal choice. They feel indulgent without being overly sweet, and they’re sturdy enough to pack for lunches or serve at gatherings. Once you’ve tried these, you’ll want to keep them in your rotation all year round.

Why You’ll Love This Recipe

Simple and Wholesome Ingredients: Made with oat flour, rolled oats, blueberries, and maple syrup, this recipe uses pantry staples and is naturally gluten-free.
Perfect Texture: A chewy oat crust meets a juicy fruit center and golden crumb topping in every bite.
Customizable and Allergy-Friendly: Easily adaptable for vegan or dairy-free needs and adjustable to personal flavor preferences.
Great for All Occasions: Whether it’s a holiday breakfast, afternoon snack, or potluck dessert, these bars are always a hit.
Make-Ahead Friendly: These bars store beautifully, making them perfect for meal prep or baking in advance.

Ingredients

For the crust and crumble:

Gluten free oat flour or all-purpose flour
Old-fashioned rolled oats
Brown sugar or coconut sugar
Ground cinnamon
Baking soda
Salt
Butter or vegan buttery stick
Vanilla extract
Almond extract

For the filling:

Fresh or frozen blueberries
Pure maple syrup
Cornstarch or arrowroot starch
Almond extract
Lemon zest (optional)
Salt

Variations

Use different berries: Swap blueberries for raspberries, blackberries, or a mixed berry blend.
Add nuts: Chopped pecans or almonds in the topping add crunch and richness.
Make it vegan: Use vegan butter and ensure your sugar is vegan-certified.
Add lemon glaze: Drizzle a simple glaze of lemon juice and powdered sugar over the bars once cooled.
Change the sweetener: Use honey or agave instead of maple syrup if preferred.

How to Make the Recipe

Step 1

Preheat your oven and line an 8×8-inch pan with parchment paper for easy removal.

Step 2

In a large bowl, mix together the oat flour, oats, brown sugar, cinnamon, baking soda, and salt.

Step 3

Add melted butter, vanilla extract, and almond extract to the dry ingredients. Mix until the mixture resembles a moist crumble.

Step 4

Press about two-thirds of the mixture into the bottom of the prepared pan to form the crust.

Step 5

In a separate bowl, toss the blueberries with maple syrup, cornstarch, almond extract, salt, and lemon zest if using.

Step 6

Spread the blueberry mixture evenly over the crust layer.

Step 7

Sprinkle the remaining crumble mixture on top of the blueberries.

Step 8

Bake until the top is golden and the blueberry filling is bubbling, then let cool completely before slicing into bars.

Tips for Making the Recipe

Use parchment paper to make removing the bars from the pan easy and clean.
Don’t skip the cooling step—the bars need time to set properly.
Use fresh or frozen blueberries without thawing frozen ones; this prevents excess moisture.
Taste the filling before baking and adjust sweetener if your berries are extra tart.
Keep the crumble loose—don’t over-mix, or it will form a dough instead of a crumbly topping.

How to Serve

These bars are delicious served:

As a sweet addition to a breakfast spread
With coffee or tea for an afternoon snack
Warm with a scoop of vanilla ice cream for dessert
Chilled straight from the fridge
Cut into small squares for a party tray or brunch buffet

Make Ahead and Storage

Storing Leftovers

Store bars in an airtight container at room temperature for up to 2 days, or refrigerate for up to 5 days for longer freshness.

Freezing

Freeze cooled bars in a single layer, then transfer to an airtight container or freezer bag for up to 2 months. Thaw in the fridge overnight before serving.

Reheating

Serve bars cold, at room temperature, or warm briefly in the microwave for 10–15 seconds.

FAQs

1. Can I use frozen blueberries?

Yes, just use them straight from the freezer—no need to thaw.

2. Are these bars gluten-free?

Yes, as long as you use certified gluten-free oats and oat flour.

3. Can I make these bars vegan?

Yes, substitute the butter with a vegan butter alternative and ensure all other ingredients are plant-based.

4. What can I use instead of oat flour?

You can use all-purpose flour or make your own oat flour by blending rolled oats.

5. Do I need to refrigerate the bars?

Not necessarily, but refrigeration helps them stay fresh longer and hold their shape better.

6. Can I reduce the sugar?

Yes, you can reduce the brown sugar slightly or substitute with coconut sugar for a less refined option.

7. Will these bars hold their shape?

Yes, if fully cooled before cutting, they slice into neat, firm bars.

8. Can I add lemon juice to the filling?

Yes, but be cautious—it will add tartness and thin the mixture slightly.

9. How do I make the bars less crumbly?

Make sure your butter is well incorporated and don’t over-bake the bars.

10. Can I use other fruits besides blueberries?

Absolutely. Strawberries, raspberries, blackberries, or a combination work great.

Conclusion

Blueberry Oatmeal Crumble Bars are the kind of treat that delivers both comfort and simplicity. With a golden oat crust and a juicy berry center, these bars offer everything you love about homemade desserts in a format that’s easy to bake, serve, and enjoy. Whether you’re looking for a healthier alternative to store-bought sweets, a make-ahead snack, or a crowd-pleasing brunch addition, these bars rise to the occasion. With just a few basic ingredients, you can create something truly special that’s as wholesome as it is delicious.