Preheat oven to 350 degrees. If desired, line cupcake pans with paper liners. You may also spray cupcake pas with a butter and flour combination spray that can be found in your local grocery store.
Combine all ingredients in a large mixing bowl. Mix at low speed for 30 seconds while scraping bowl. Mix at high speed for 3 minutes, scraping bowl every minute.
Spoon cupcake batter into liners until they are 1/2 to 2/3 full. You should have enough batter for 24-36 cupcakes.
Bake for 20 to 25 minutes or until toothpick inserted in center comes out clean.
Cool 10 minutes in pans then move to wire rack to cool completely.
Frost your peanut butter and chocolate cupcakes any way you want. You could even try just spreading extra peanut butter as your frosting.