Dissolve gelatin in 3/4 cup boiling water. Add 1/2 cup cold water; set aside at room temp. Mix and bake cake, as directed on box, in a 13x9x2" pan. Cool 20-25 minutes. Poke deep holes thru top of warm cake (still in pan) with fork. Slowly pour gelitin mixture into holes. Refrigerate cake while preparing topping.
TOPPING: In a chilled (best in a stainless steel bowl)deep bowl blend and whip topping mix, instant pudding and cold milk till stiff (3-8 minutes). Immediately frost cake. Cake may be stored in refrigerator and served chilled. Frosted cake may be frozen. It gets better the longer it stays in the refrigerator