Preheat your oven to 375 degrees. Oil a 8×8 inch baking dish and set aside.
In a small sauce pan, bring the blueberries, agave nectar, lemon juice, and water to a boil over medium high heat. When it boils, stir in the vanilla and arrowroot mixture. Remove from heat and allow to cool. The mixture will thicken as it cools. If you are using corn starch instead of arrowroot, you will need to stir the mixture a little longer as it cooks and thickens before you remove it from the heat.
Process 1 1/2 cup of the oats in your blender or food processor until they are a fine powder. Combine the processed oats, the remaining 1 1/2 cups of rolled oats, cinnamon, baking powder, and salt in a bowl and mix well.
Add the applesauce, agave nectar, and vanilla and mix until everything is well combined. Add the coconut oil and use your hands to incorporate it into the mixture evenly. The oats mixture will be thick and resemble cookie dough.
Press about half of the mixture into the bottom of your baking dish. Press it down firmly so that it reaches the edges of the pan and forms an even bottom crust. Pour the blueberry mixture on top of the crust layer. Finally, sprinkle the rest of the oat mixture on top of the blueberry mixture in crumbles. Bake for 30 minutes in the preheated oven. Allow to cool before cutting into squares. Store in the refrigerator. Enjoy!