Blueberry Crumble bars are a simple delicious treat... that just happen to also be healthy! This gluten free one bowl recipe is a must try. My 9 ingredient blueberry oat bars are the perfect grab and go breakfast when you’re in a rush! They’re very, very easy to make. These simple healthy blueberry oat crumble bars are topped with the most delicious oat crumble that doubles as the crust meaning less prep for you! Win-win!
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 3/4 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.