Bake strawberry cake according to directions on box

Let cool

Mix small box of strawberry jello with 1 cup boiling water (do not add the cup of cold water), and mix well until dissolved

Poke cake all over with fork and pour jello mixture on top, evenly

Let cool in refrigerator for at least 1 hour

Spread half of container of frozen strawberries on top of the cake

Mix the other half with the tub of cool whip and spread on top as frosting