Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
Mix together rice flour, white sugar, cocoa powder, brown sugar, salt, and baking powder in a large bowl; add coconut milk, applesauce, flaked coconut, and coconut oil. Blend mixture until thickened; pour into the prepared baking dish.
Bake in the preheated oven until the top is dry and the edges have started to pull away from the sides of the pan, about 30 minutes. Cool for about 10 minutes before cutting into 12 squares.