For the crust and crumble:
- 1 ½ cups gluten-free oat flour (or sub-all-purpose flour)
- 1 cup old-fashioned rolled oats, gluten-free if desired
- ½ cup packed brown sugar (or sub coconut sugar but you may not get the best ‘crumble’)
- ½ teaspoon ground cinnamon
- ¼ teaspoon baking soda
- ¼ teaspoon salt
- 8 tablespoons butter or vegan buttery stick, melted
- 1 teaspoon vanilla extract
- ¼ teaspoon almond extract
For the filling:
- 2 1/2 heaping cups fresh or frozen blueberries
- 3 tablespoons pure maple syrup
- 1 tablespoon cornstarch or arrowroot starch
- ⅛ teaspoon almond extract
- Optional to make the with a hint of lemon flavor: zest from 1 lemon
- Pinch of salt
- Preheat the oven to 350 degrees F. Line an 8×8 inch pan with parchment paper and generously spray with nonstick cooking spray. Set aside.
- Make the base + topping: In a large bowl, use a fork to mix together the oat flour, oats, coconut sugar, cinnamon, baking soda, and salt. Add in melted butter, vanilla extract, and almond extract and stir until a nice crumble forms and dough begins to clump together.
- Place 1 3/4 cups of the mixture into the prepared pan and place the remaining mixture into the fridge (the remaining mixture will be used for the topping). Use your hands to evenly press the dough to the bottom of the pan.
- Next, make your blueberry pie filling: place a medium pot over medium heat. Add in blueberries, maple syrup, almond extract, cornstarch (or arrowroot), and salt. Use a wooden spoon to press down and break down the blueberries just a bit.
- Bring to a boil, then reduce heat and cook for 3-5 more minutes until the mixture is thickened up and nicely coats the back of a spoon.
- Pour mixture over the crust and use a spoon to evenly spread.
- Take the remaining topping out of the fridge. By now there should be some nice crumbles that have clumped together. Sprinkle the topping over the blueberry filling.
- Bake for 30 minutes or until filling is bubbly and the topping is golden.
- Allow bars to cool completely on a wire rack before transferring to the fridge to chill. Bars are delicious served at room temperature or straight out of the fridge. Use a sharp knife to cut into 16 bars before serving.