Once the cake is baked. Let cool on cooling rack about 5 minutes. Poke holes all over cake,( I use end of wooden spoon). making sure not to go completely through the bottom of the cake.
Stir your fudge sauce, and pour all over cake; spreading evenly making sure is penetrating holes of cake. Refrigerate until cool, and ready to frost with the whipped topping.
Whip the cream along with the vanilla and sugar until it forms soft peaks. Spread the whipped cream over the top of the cake evenly. Place in the refrigerator to chill for at least an hour before serving.