FOR THE CAKE: Prepare cake mix according to box directions and bake in a 9x13 pan. Just before the cake is done baking combine the sweetened condensed milk, peanut butter and chocolate chips in a small bowl. Heat in the microwave in 30 second intervals stirring well after each until completely melted and smooth. Set aside. Remove cake from oven and with the end of a wooden spoon or something similar poke holes all over the top of the cake. Take reserved peanut butter mixture and pour all over the top of the cake. Let the cake cool completely.

CHOCOLATE WHIPPED TOPPING: In the bowl of your stand mixer combine the whipping cream, powdered sugar, cocoa powder and vanilla. Using the whisk attachment beat on low speed until everything is combined then at high speed until you have stiff peaks. Spread over the cooled cake. Top with chopped peanut butter cups and drizzle with warmed hot fudge sauce. Refrigerate until ready to serve. Store leftovers in the refrigerator.