Want an exotic dessert? Adding tropical fruit to a cake mix gives it an interesting texture and flavor. Select a cake mix that can be baked in a tube pan. Substitute 1 cup drained and diced tropical fruit for 1/4 cup water and follow directions on the package for a tube-pan cake. Cooking may diminish the fruit's fresh flavor, so enhance the tropical taste by adding diced or mashed tropical fruit to the frosting.