01 -
Preheat the oven to 350°F. Prepare the cake mix according to package instructions and bake in a 9×13-inch baking dish until done.
02 -
Using a wooden utensil handle, poke evenly spaced holes about 1 inch apart across the surface of the warm cake.
03 -
Warm the hot fudge topping as per package directions until fluid. Spoon the hot fudge evenly into the holes throughout the cake.
04 -
Microwave the peanut butter in 15-second intervals, stirring until smooth. In a separate bowl, whisk together instant vanilla pudding mix and milk until smooth but not thickened. Quickly whisk in the warmed peanut butter until fully combined.
05 -
Pour the peanut butter pudding mixture evenly over the cake. Use the back of a spoon to press the pudding gently into the holes, spreading remaining pudding over the top.
06 -
Refrigerate the cake for 2 hours to allow the pudding to set.
07 -
Spread the whipped topping evenly over the set pudding layer. Return the cake to the refrigerator for an additional 2 hours or longer to fully chill.
08 -
Just before serving, drizzle chocolate syrup over the top and sprinkle with chopped Reese’s peanut butter cups. Slice and serve chilled.