Preheat oven to 350 degrees and lightly grease an 8X8 baking dish.
In a bowl combine blueberries, lemon zest, lemon juice, ¼ cup coconut sugar, and tapioca or corn starch. Stir to thoroughly coat berries.
In a separate bowl combine flour, oats, salt, remaining coconut sugar, and baking powder.
Using your fingers or a pastry blender cut in coconut oil into flour mixture until only pea size pieces remain.
Add flax eggs or applesauce to flour mixture and stir to thoroughly combine. Mixture should be crumbly.
Press just over half of the mixture into the bottom of baking dish and spread to cover forming the bottom crust. Be sure to apply enough pressure that the mixture holds together. I placed a piece of parchment paper over top and rolled a small can back and forth.
Spread blueberries in an even layer over bottom crust.
Crumble remaining crust mixture over the top of blueberries.
Bake for 55-60 minutes until crumb topping is lightly browned.
Allow to cool completely before cutting.
Store in a container in the fridge.