This easy Blueberry Crumble Bars recipe features two layers of buttery, crispy baked oats sandwiching a juicy, jammy blueberry center that’s bright with fresh lemon. Perfect for grab & go breakfasts, snacking, or a simple summer dessert!
Make the most of summer’s berry bounty with this easy recipe for Blueberry Crumble Bars! It features a buttery oats crumble that doubles as a pressed-in crust and a crispy crumb topping, plus a layer of sweet, jammy blueberries sandwiched in between. I squeezed some fresh lemon juice and zest into the berry layer, which makes this blueberry treat shine even brighter. Enjoy the blueberry bars for breakfast or brunch, or as a snack – or serve them as a simple summery dessert!
Why WE Love These Blueberry Crumble BarS
One of the biggest highlights of summer is the abundance of fresh, local fruits and vegetables. We go strawberry and blueberry picking almost every year, and have our own raspberry patch – these give us buckets of the best tasting berries you can imagine. So, of course, I have to bake with them! Here’s why my family loves this recipe:
- Fresh & juicy-jammy. Summer’s best sweet-tart blueberries are truly the star of this blueberry crumb bar recipe. Even better if they’re recently picked!
- Cozy. Around here, we adore buttery, crispy baked oats layers (like the topping on strawberry rhubarb crisp and my favorite apple crisp) – and this recipe features TWO of these layers. The bottom layer is pressed in, like an oat shortbread. And the top layer is in the form of crunchity crumbles. LOVE!!
- So easy. This simple recipe calls for common ingredients and roughly 15 minutes of hands-on time.
- Versatile. These bars are a great mid-morning or afternoon snack, a fun little breakfast on-the-go, or dessert.
Recipe Ingredients
Here’s a look at the ingredients in these blueberry oatmeal crumble bars. Scroll down to the printable recipe card at the end of this post for the exact ingredient amounts.
For the Crumble Crust & Topping
- Flour – All-purpose flour helps create the crumble mixture.
- Oats – I use old-fashioned oats, which are larger and hold up better than quick cooking (instant) oats. They add texture and crunch to the crumble after it’s baked.
- Brown sugar – This adds rich, warm sweetness.
- Baking powder – This ingredient allows the crumble to rise and take on more crispy texture.
- Cinnamon – For a touch of warm spiced flavor.
- Butter – This helps to hold the crumble mixture together, plus gives rich flavor.
- Maple syrup – I love the natural sweetness and unique flavor that this adds to the crumble.
For the Blueberry Layer
- Blueberries – I recommend using fresh berries, for the best flavor and texture. See my notes below about using frozen berries.
- Sugar – Granulated sugar sweetens the blueberries and helps to create a sweet, jammy texture.
- Cornstarch – This ingredients thickens and binds together the blueberry layer so that it doesn’t seep into the crumble crust.
- Lemon juice & zest – Use freshly squeezed lemon juice for the best, freshest flavor. I also include some lemon zest, which helps to magnify that fresh lemon flavor.
Should I Use Fresh or Frozen Berries?
I recommend using fresh blueberries for this recipe because they provide the best blueberry flavor and texture. However, you can use frozen berries in a pinch. Just incorporate them from frozen; do not thaw them first.
How To Make Blueberry Crumble Bars
See my photos below to guide you through making these fruit bars. Find the detailed instructions in the recipe card lower down.
- Prep. Preheat the oven. Line a 9″x13” pan with parchment paper, or just spray the pan well with nonstick baking spray.
- Make crumble mixture. Mix the flour, oats, brown sugar, baking powder, and cinnamon, then stir in the melted butter and maple syrup.
- Press into pan, then bake. Press two-thirds of the crumble mixture into the bottom of the pan, then bake it for 10 minutes.
- Combine ingredients for blueberry layer. Mix the blueberries, sugar, cornstarch, lemon juice, and lemon zest.
- Add blueberries to pan. Spread the blueberries evenly over the crust.
- Add crumble. Sprinkle the remaining crumble mixture over the top of the blueberries.
- Bake. Bake for 60-65 minutes. Let pan cool completely on a baking rack, then cut into bars.
Tips & Variations
I love branching out on this base recipe and trying other types of fruit or adding nuts or other flavorful tidbits. Here are are few ideas to get you started:
- Use the freshest blueberries. This should go without saying, but the freshest, sweetest blueberries will make this simple recipe spectacular.
- Add nuts. For a little extra crunch, add sliced or chopped almonds, walnuts, or pecans to the crumble topping.
- Other spices. In addition to, or instead of the cinnamon, you can try other ground spices. A little ground ginger or nutmeg is nice here, or just add more ground cinnamon.
- Swap the maple syrup. If you don’t have maple syrup, substitute honey.
- Sub in orange zest. Blueberry and orange is another great combination. For a slight flavor twist, sub in orange juice and zest for the lemon.
Serving Suggestions
Blueberry bars are a delicious choice morning, noon, or night!
- For brunch. Serve blueberry bars alongside savory brunch items like cottage cheese egg bake or overnight egg bake.
- With coffee. Enjoy a jammy blueberry bar with a cortadito, a beautiful lavender latte, or a dirty chai latte.
- Lemonade. Talk about a super fun summer treat – pour glasses of strawberry lemonade or blueberry lemonade to go with your warm blueberry crumb bars.
- Ice cream. When serving warm blueberry crumble bars for dessert, top them with scoops of vanilla ice cream. Or, go all-in on blueberries with gorgeous crème fraîche blueberry ice cream or blueberry cheesecake ice cream!
Proper Storage
I’ve outlined below a few different options for storing these bars:
- Counter – Place the bars in an airtight container and keep them on the counter for up to 2 days – just know that the crispy texture will soften with time. To retain some of that crispy crumble texture, store the bars uncovered.
- Fridge – Keep blueberry crumble bars in an airtight container in the fridge for up to 5 days.
- Freezer – Place blueberry bars in a freezer-safe container with parchment paper between layers, and store in the freezer for up to 3 months. Thaw bars in the fridge before serving.
More Blueberry Recipes To Try
- Blueberry Muffins with Crumb Topping – my grandma’s recipe!
- Blueberry Tea Cake
- Blueberry Cobbler with Orange Biscuit Puffs
- Blueberry Hand Pies
Blueberry Crumble Bars
Ingredients
For the Crumble Crust & Topping
- 2 cups all-purpose flour
- 2 cups old fashioned oats
- ½ cup brown sugar
- ½ teaspoon baking powder
- ¼ teaspoon cinnamon
- 1 cup unsalted butter, melted
- ¼ cup pure maple syrup
For the Blueberry Layer
- 3 cups fresh blueberries
- ¼ cup granulated sugar
- 2 tablespoons cornstarch
- 2 tablespoons freshly squeezed lemon juice
- 1 teaspoon lemon zest
Instructions
For the Crumble Crust & Topping
- Preheat oven to 350℉. Line a 9"x13” pan with parchment paper or spray it generously with nonstick cooking spray.
- In a medium bowl, stir together flour, oats, brown sugar, baking powder, and cinnamon. Add melted butter and maple syrup, and stir until clumps of dough begin to form.
- Press two thirds of the crumble mixture into the bottom of the pan and smooth it into an even layer. Set remaining crumble mixture aside. Bake crust for 10 minutes while you prepare the blueberry layer.
For the Blueberry Layer
- In a medium blow, stir blueberries, sugar, cornstarch, lemon juice, and lemon zest until evenly combined.
- Spread blueberry mixture evenly over the par-baked crumble crust.
- Sprinkle the remaining crumble mixture over the top of the blueberries. Bake for 60-65 minutes, or until the crumble is golden brown and crisp.
- Allow bars to cool completely in the pan. Then remove them from the pan using the parchment paper and cut into your desired size. You can also pop the bars in the fridge for an hour to make slicing even easier if needed.
Notes
Nutrition Information:
This post was first published in 2016, then updated in 2024.
Will frozen blueberries work in this recipe?