1Prepare cake according to the box instructions.
When it's done, poke holes in the cake using the handle of a wooden spoon and spread the crushed pineapple over the cake allowing the juice to soak in.
2in a skillet, combine the butter and brown sugar until melted, add the sliced bananas and sautee for 1 minute on each side. Add the rum and liquer and flambee until the alcohol burns off. Set aside to cool.
3Cover the cake in the whipped cream.
Place banana slices on top until covering the cream and spoon the sauce over the bananas. Top with chopped nuts.