Preheat oven to 350°F.
Add the oats to a blender and grind into a flour.
Add the dates to the oat flour in the blender and blend until it is a fine crumble.
Add this mixture to a mixing bowl along with the almond flour, baking powder, baking soda and cinnamon and stir.
Stir in the vanilla and water and mix until it starts clumping together slightly, adding more water a tablespoon at a time if necessary.
Press ¾ of the mixture into the bottom of a lined 9x9 pan.
Blend ½ cup of the blueberries, dates, water, arrowroot flour and lemon juice until dates are pulverized.
Add this mixture along with the remaining 2 cups of blueberries to a saucepan and cook on medium until mixture thickens slightly.
Pour mixture over the crust and smooth surface.
Crumble remaining crust mixture over the top of the blueberry mixture.
Bake for 30 minutes.
Let cool before cutting. Bars will turn more firm once chilled.
Store in an airtight container in the fridge for up to a week.
