Preheat oven to 350 degrees. Prepare cake mix as directed on box, then fill 24 paper-lined muffin cups about 3/4 full with cake batter. Bake approximately 20 minutes. Cool only 30 minutes. Cupcakes still need to be warm to fill.
Pour milk into medium bowl. Add dry pudding mix. Beat with wire whisk 2 min. or until well blended. Add peanut butter; beat well. Spoon into a small decorator's bag with a Specialty tip #230 on the end. Now insert tip into center of each cupcake and fill with about 1 tablespoon of the peanut butter filling into each cupcake. It might be tricky at first, but you will get the hang of it. IF you do not have any decorator tips on hand...then cut a small hole in the top of the cupcake and then fill with one tablespoon of PB filling..then replace cake piece on top.
Microwave whipped topping and chocolate in a small bowl on high for 1 1/2 minutes. Dip the top of each cupcake into glaze. Sprinkle with chopped peanuts. Store in refrigerator.
***If you want, I believe this could be converted into a cake as well. Bake your cake in a 9x13 pan, when cake is done keep in pan..then take your decorator's tip as explained above and inject the filling in about 15 different sections of the cake..one at each square that you would end up cutting a piece for someone. Then pour your frosting over the entire cake..top with peanuts. Be sure to refrigerate before serving.