1 can cherry pie filling
1 can crushed pineapple
1 box yellow cake mix
1 stick butter

Spread the cherry pie filling in the bottom of a 9 x 9 inch ungreased cake pan. Pour the pineapple evenly on top of the cherries. Then spread the dry cake mix on top of the pineapple. Melt the butter and pour over the cake mix. Sprinkle with chopped nuts, if desired. Bake at 350 degrees until cake is done (approximately 45 minutes) and butter is crusty on top.