Mix cake according to the directions on the box. Put in a greased and floured 13 x 9 pan. Bake at 350 degrees for about 25 minutes or until done. While cake bakes, mix Jello in boiling water. Let Jello cool. When cake is cool, make holes in top of the cake with a fork. Pour Jello over the cake. Refrigerate for a few hours; then spread Cool Whip on top of the cake. When ready to serve, slice and top with fresh strawberries.
You can use different flavors of Jello and fruit. Peach Jello is very good too.