01 -
Preheat oven according to cake mix instructions. Grease and lightly flour a 9x13-inch baking dish. Prepare the cake mix as directed, then stir in 1 cup creamy peanut butter until smooth. Pour batter into dish.
02 -
Bake the cake for 30 to 35 minutes as per package directions. Remove and allow to cool for 15 minutes.
03 -
Using the handle of a wooden spoon or skewer, evenly poke holes approximately 1 inch apart across the cake surface.
04 -
Whisk together sweetened condensed milk and melted peanut butter until smooth. Slowly pour over the cake to fill all holes, allowing the cake to absorb the filling completely.
05 -
Refrigerate the cake for at least 1 hour to let flavors meld and the filling set slightly.
06 -
Spread whipped topping evenly over the chilled cake surface with a spatula.
07 -
Sprinkle mini chocolate chips and chopped peanut butter cups over the topping. Cut into 12 squares and serve chilled.