Preheat oven to 350 degrees. Make cake as per instructions on the box using softened butter instead of vegetable oil. Then pour into 2 (8) inch round greased pans. Cooking time is the same for the substitution of butter. Let both cakes cool on a wire rack in the pans for 20 minutes. Then turn upside down and gently tap them out. And let them sit on wire rack for at least 20 minutes until completely cool. Slide a knife to cut off the tops of the cakes to get an even surface to place cherries. Place first cake on serving dish and then top with one can of cherries. Then place other cake on top. Ice the sides of the cake with the cool whip creating an edge at the top to hold the other cherries in. (about an inch or two) Then spoon half of the second can of cherries into the middle being careful not to drip over the cool whip edge. Put in the refrigerator to chill for at least 2 hours before serving. Can be made a day ahead if you have a lid on your serving dish.