1 yellow pudding cake mix
20 oz. crushed pineapple
1 (3 oz.) pkg. vanilla instant pudding
1 (9 oz.) carton Cool Whip

Bake yellow pudding cake mix. Cool slightly. Poke holes all over with a meat fork while still warm. While still warm, pour a 20 ounce can (juice and all) of crushed pineapple over the top, spreading the fruit evenly. When cake is cool, spread a prepared package of vanilla instant pudding mix over the top. Top cake with a 9 ounce carton of thawed Cool Whip. Refrigerate until ready to serve.

NOTE: If I want the cake especially "yummy" and tall, I use a family size package of pudding and a larger carton of Cool Whip.