Bake cake mix according to the package instructions in a 9x13" pan. (OR make my Homemade Chocolate Cake baked in a 9x13" pan. 1 box devil's food cake mix and ingredients to prepare (listed on package) OR my homemade chocolate cake
While the cake is still hot, poke holes in the cake with the end of a wooden spoon.
In a small bowl, combine the sweetened condensed milk and 1/2 cup of peanut butter. (See notes below if it seems too thick to pour)
1 14-ounce can sweetened condensed milk, 0.5 cup creamy peanut butter
Pour over the cake slowly, allowing the mixture to soak into the holes; let cool.
Stir together the whipped topping and remaining 1/4 cup of peanut butter and spread over the cooled cake.
1 8-ounce tub whipped topping
Top with additional peanut butter, fudge sauce and peanut butter cups.
0.25 cup creamy peanut butter, peanut butter cups, additional peanut butter and fudge topping
Refrigerate until ready to serve.