Chocolate + Peanut Butter + Cupcakes = Yes. At first I thought it was chocolate chip cookie dough on the very top-- which makes me think that could be tried, too. Chocolate batter, gob of peanut butter in the middle, cookie dough on top.
Chocolate Cupcakes with Peanut Butter Cookie Frosting by annieseats. These are pretty much like buckeye candy cupcakes. Maybe they'd be better with a peanut butter frosting and the peanut butter "cookie" as a filling?