This is from my DD Jen.
Use a boxed butter cake recipe. Cook as directed. After the cake cools poke a LOT of holes all over the cake with a fork. It is very important to poke a LOT of holes. Pour a can of condensed milk over the cake. Let that soak in until it looks absorbed. Top with Cool Whip and the fruit of your choice. She likes strawberries, but you can also use coconut, cherries, blueberries, etc. Store the cake in the fridge. She says this is the best cake she has ever eaten.