Grease mini-cupcake pans with nonstick cooking spray. Mix cookie dough with peanut butter just until swirled. Press 1 rounded teaspoonful of dough into each of the prepared cups. Bake for 12 minutes. Cool in pans. Run a small knife carefully around the edge. Remove from pans to a cooling rack. When completely cool, place a scant teaspoonful of frosting in the center of each cookie.