Melt butter or margarine over low heat. Add marshmallows and stir until melted. Remove from heat, add vanilla and Rice Krispies. With buttered hands, press mixture into a buttered pizza pan (or try it free-form, about 1/2 inch thick).
Blend the cream cheese and confectioners sugar in a bowl. Fold in Cool Whip. Spread the filling over the cooled crust.
For the topping:
Slice fresh fruits and set out for the kids to pile on!