Preheat oven to 350 °F. Spray a 9x13 inch baking dish with cooking spray.
In a small bowl, combine all the dry ingredients - protein powder, oats, all-purpose flour, coconut flour, salt, baking powder, and cinnamon. Mix until all ingredients are combined.
In a separate large bowl, add the wet ingredients - egg, applesauce, pancake syrup, almond milk, egg whites, vanilla, and butter extract. Using a hand mixer, blend ingredients until mixed thoroughly.
Add in dry ingredients to the wet ingredients slowly, mixing with the hand held mixer some before adding more. Blend until all ingredients are completely combined. Fold in half of the dried blueberries with a spoon.
Pour oat batter into sprayed dish. Sprinkle with the rest of the dried blueberries. Bake for 20-25 minutes or until center comes out clean with a toothpick. Be careful not to over-bake.
While the oat bars are cooking, gather the ingredients for the icing. Combine the protein powder, yogurt, and almond milk in a small bowl until combined. Store in the refrigerator to thicken and cool before ready to use.
When the oat bars are done, take out of oven and let cool. Once bars have cooled down, add icing*.