1. In bowl, add dry cake mix and dry pudding mix. Stir.
2. In another bowl, combine wet ingredients and eggs of cake mix with the buttermilk. Beat with mixer until blended.
3. Add wet mixture to dry cake mix mixture. Beat for 2 minutes until thoroughly blended and smooth.
4. fold in cherries and nuts.
5. Put in sprayed 9x13 pan and bake according to box directions. Allow up to 5 minutes more baking time due to added moisture. Use toothpick to test doneness.
6. While cake is baking, heat pineapple and brown sugar until sugar is melted.
7. Poke holes in the top of the cake with something that will make an 1/8 to 1/4 inch hole. I use the handle of a wooden spoon, and pour pineapple mixture over it evenly. Spread with cool whip and top with coconut and a dusting of walnuts.
Refrigerate for an hour before serving.