Bake cakes for 35 minutes. Then test, with a toothpick that comes out clean, for doneness. If not done, check again every 5 minutes. When done, cool for a few minutes on a rack. Invert the plain (no blueberries) layer onto plate. Invert the layer with the blueberries onto a FLAT metal cookie sheet. When completely cool, apply 1 cup plain whipped topping on top of plain bottom cake layer. Sprinkle with fresh raspberries.