Blueberry Crumble bars are a simple delicious treat... that just happen to also be healthy! These bars are an easy breakfast bar and snack made in one bowl with no mixer, and they are gluten free when you use gluten free oats. A buttery oat crust doubles as the crumble topping over a jammy blueberry filling, so there is less work and plenty of flavor.
Blueberry Crumble Bars Recipe
Anything that makes a busy morning easier is a win in our house, and these bars deliver. They are soft and tender with a slightly chewy bite from the oats, and a hint of cinnamon makes them taste like blueberry pie. They are not too sweet, so the blueberries really shine at breakfast, brunch or snack time, or as a lighter dessert.
Blueberries were a breakfast staple when I was growing up, stirred into pancakes and oatmeal or baked into warm muffins, so putting them into a bar felt like a natural step. Living in Canada means fresh berries are not always around, so frozen ones are our go-to, and they work beautifully here. Mom even called these one of the best desserts I have made in a long time.
Because they are made with oats and oat flour, these bars are also a friendly option for potlucks and snack boxes. If you love our Banana Oat Crumble Muffins, you will love this!
What are Blueberry Crumble Bars?
Blueberry crumble bars, also called blueberry oat bars, have a soft oat crust, a jammy blueberry filling and a crumbly oat topping. Here the crust and crumble come from the same dough, so there is just one mixture to make.
What is in Blueberry Crumble Bars?
Crumble and Crust Ingredients
- Oat Flour - using oat flour keeps these bars gluten free. You can use store-bought oat flour or make your own by simply adding oats to a blender or food processor and blending until smooth.
- Oats - I love baking with large flake oats rather than instant oats. Instant oats are often processed or more ground down for quicker cooking.
- For gluten free bars ensure your oats state they are gluten free. Oats are naturally gluten free but are often produced and packaged in factories/assembly lines that also process flour so there is potential cross contamination.
- Butter - these healthy bars use as little butter as possible. Butter is needed to keep the crust together and to help the crumble crisp up and stick together while baking.
- Brown Sugar - the rich molasses flavor of brown sugar really elevates the crust and crumble of these bars.
- Baking Soda - just a pinch of baking soda keeps the crust and crumble light and airy.
- Vanilla and Cinnamon - I love the subtle hint of cinnamon in blueberry pie and crumble. Vanilla extract is a more common pantry baking ingredient but I have left a note in the recipe that you can also use a splash of almond extract for an added nutty flavor.
Filling Ingredients
- Blueberries - I love this recipe because you can use fresh or frozen blueberries! Living in Canada we don't have the pleasure of having garden fresh blueberries all year round so I often use frozen berries for this recipe. Rest assured once summer comes around I'll be sharing lots of recipes and pictures of our blueberries bushes in our garden!
- Vanilla - the vanilla brings out the natural sweetness of the blueberries and adds a subtle vanilla aroma
- Brown Sugar - I love the flavor of brown sugar, the molasses adds a nice richness to the filling. You can sub for regular white sugar or sweetener of choice.
- Cornstarch - often to make jam or pie fillings a large amount of sugar is needed which act as a sweetener but also thickens the filling. Cornstarch is a healthier alternative than adding more sugar. The cornstarch thickens the filling perfectly... and keeps the bars gluten free too!
How to Make Blueberry Crumble Bars
Full Printable Recipe at Bottom of Page
Prepare the Crust and Crumble
1 Line an 8” x 8” baking dish (or 9” x 9” for thinner bars) with parchment paper. Leave enough parchment paper on both sides to overhang. This overhang will be used as ‘handles’ to pull the bars out of the tray after baking and chilling. Set aside.
2 In a large bowl, mix together all of the crust and crumble ingredients. Use a fork to mash the room temperature butter into the oat flour and oats until the dough starts to come together and forms large crumble pieces. The mixture should be crumbly, not smooth.
3 Place 1 and ¾ cups of the mixture into the prepared pan and put the remaining mixture in the fridge, this will be used for the crumble topping. Use your hands or the bottom of a cup to evenly press the dough in the bottom of the pan. Ensure the dough is pressed evenly together to form the crust.
4 Place the pan in the fridge to chill the crust while you prepare the filling. This will make it easier to evenly spread the filling over the crust without it crumbling.
Prepare the Blueberry Filling
1 In a medium sized pot on medium heat, add all of the filling ingredients except the cornstarch. Stir continuously until the blueberries start to break down. Use the back of the a spoon or spatula to gently press and breakdown the blueberries. Once the blueberries start to breakdown and release their juices, add in the cornstarch and quickly stir until evenly combined.
2 Bring the blueberry mixture to a boil then the reduce heat to a simmer. Cook for about 5 minutes, or until the mixture is thickened and coats the back of a spoon.
Assemble the Bars
1 Preheat oven to 350°F.
2 Remove the chilled crust from the fridge and pour the blueberry filling mixture on top. Use a spoon or spatula to evenly spread it over the crust.
3 Sprinkle the remaining crumble topping over the blueberry filling.
4 Bake for 25 - 30 minutes or until the filling is bubbling and the crumble topping is golden brown and crisp.
5 Remove from the oven and place the baking dish on a wire rack. Allow the bars to cool at room temperature completely, approximately 1 hour.
5 Use the parchment paper ‘handles’ to remove the baked bars from the baking dish. Slice into 16 bars and serve. The bars are delicious served at room temperature, or chilled fresh out of the fridge.
Tips for the Best Blueberry Crumble Bars
- Room Temperature Butter - when preparing the crust and crumble be sure to use room temperature butter... unless you want a workout! To combine the oat flour and oats with the butter you want the butter to be soft, if not you will be trying to mix the butter into the oats with a lot of elbow grease.
- Chill the Crust - after you have prepared the crust in the baking dish, pop the pan in the fridge while you make the filling. The butter will harden so that when you spread the blueberry filling mixture over the crust it will not crumble your crust.
- Cool the Bars - before slicing the bars be sure to fully cool the bars at room temperature for at least 1 hour, or chill them in the fridge. If you try slicing the bars fresh out of the oven they will crumble and fall apart as the blueberry filling will be too warm. Allow the bars to fully cool and then slice!
FAQS
There is no need to reheat them. Enjoy them at room temperature or chilled straight from the fridge.
Place the sliced bars in a single layer in an airtight container, with parchment or wax paper between layers if you stack them. They keep in the fridge for up to 1 week.
Yes! Bake and slice the bars, let them cool, and store them for grab-and-go breakfasts all week.
Yes. Freeze them in a single layer in an airtight container, stacked with parchment between layers, or wrapped individually in plastic wrap. Freeze for up to 3 months. Thaw in the fridge.
No. Quick-cook and instant oats are finer than regular oats and cook differently, which makes the crust and crumble dry and crumbly. Large flake oats work best.
Yes, both work. We often use frozen berries since fresh ones are not always available year round.
They are lighter than many store-bought bars, made with oats and oat flour and with as little butter and sugar as possible. The oats bring fiber, which helps keep you full.
Usually they were sliced while warm. Let them cool completely, about 1 hour, or chill them, and make sure the crust is pressed firmly and the filling has thickened.
Use an 8 inch square baking dish for thicker bars or a 9 inch square dish for thinner bars. Either way, slice into 16 bars.
Blueberries contain antioxidants, vitamin C and potassium, and they add natural sweetness to these bars.
Looking for More Simple Breakfast Ideas?
- Mini Berry Dutch Babies
- Banana Oat Crumble Muffins
- Chocolate Chip Banana Bread
- Strawberry Cheesecake French Toast
Enjoy!
- Sab
Blueberry Crumble Bars
Equipment
Ingredients
Crust and Crumble
- 1 ½ cup oat flour (or all purpose flour)
- 1 cup oats (preferably large flake, or quick cooking oats)
- ½ cup brown sugar (packed )
- ½ teaspoon cinnamon
- ¼ teaspoon baking soda
- ¼ teaspoon salt
- ½ cup butter (1 stick, room temperature)
- 1 teaspoon vanilla extract (or ½ teaspoon vanilla extract and ½ teaspoon almond extract)
Filling
- 2 ½ cups blueberries (fresh or frozen)
- 2 tablespoon brown sugar
- 1 tablespoon cornstarch
- ½ teaspoon vanilla extract
Instructions
- Line an 8” x 8” baking dish (or 9” x 9” for thinner bars) with parchment paper. Leave enough parchment paper on both sides to overhang. This overhang will be used as ‘handles’ to pull the bars out of the tray after baking and chilling. Set aside.
Prepare the Crumble and Crust
- In a large bowl, mix together all of the crust and crumble ingredients. Use a fork to mash the room temperature butter into the oat flour and oats until the dough starts to come together and forms large crumble pieces. The mixture should be crumbly, not smooth.
- Place 1 and ¾ cups of the mixture into the prepared pan and put the remaining mixture in the fridge, this will be used for the crumble topping. Use your hands or the bottom of a cup to evenly press the dough in the bottom of the pan. Ensure the dough is pressed evenly together to form the crust.
- Place the pan in the fridge to chill the crust while you prepare the filling. This will make it easier to evenly spread the filling over the crust without it crumbling.
Prepare the Filling
- In a medium sized pot on medium heat, add all of the filling ingredients except the cornstarch. Stir continuously until the blueberries start to break down. Use the back of the a spoon or spatula to gently press and breakdown the blueberries. Once the blueberries start to breakdown and release their juices, add in the cornstarch and quickly stir until evenly combined.
- Bring the blueberry mixture to a boil then the reduce heat to a simmer. Cook for about 5 minutes, or until the mixture is thickened and coats the back of a spoon.
Assemble and Bake
- Preheat oven to 350°F.
- Remove the chilled crust from the fridge and pour the blueberry filling mixture on top. Use a spoon or spatula to evenly spread it over the crust.
- Sprinkle the remaining crumble topping over the blueberry filling.
- Bake for 25 - 30 minutes or until the filling is bubbling and the crumble topping is golden brown and crisp.
- Remove from the oven and place the baking dish on a wire rack. Allow the bars to cool at room temperature complete, approximately 1 hour.
- Use the parchment paper ‘handles’ to remove the baked bars from the baking dish. Slice into 16 bars and serve. The bars are delicious served at room temperature, or chilled fresh out of the fridge.
Mellisa says
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