1 box yellow cake mix
1 cup crushed pineapple
1 cup pumpkin puree (not pumpkin pie mix)
1 tsp pumpkin pie spice
1 tsp vanilla or almond extract (or a combo)
Blend well and bake according to the box. Here's a tip, if you are making a cake in a deep pan or bowl, bake at 325 instead of the standard 350. It will definitely take longer but this reduces the risk of the cake ending up over cooked on the outside and still runny on the inside. Our baseball took over an hour this way but I've done enough to know this was the best way to bake it.
Decorate with homemade chocolate icing and a little green coconut grass! Let me know if you are interested in that recipe, I'll gladly share.