Follow directions on brownie box for brownies. Use a foil pizza pan spread so bottom covered. Bake 350 degrees for 20-23 minutes. Adjust time depending on oven. (I check first time at 20 minutes) Cool completely. For stability I put a regular pizza pan under the foil one for baking.(Larger than the foil one)
With mixer (on medium speed) cream together cream cheese, powdered sugar, vanilla and cool whip . Spread cream cheese mixture on cooled brownie.