Ingredients

18.25 oz box yellow cake mix

1 1/3 cups water

1/3 cup smooth peanut butter

1/3 cup vegetable oil

3 eggs

1 teaspoon vanilla extract

Frosting:

2 sticks salted butter, at room temperature

1 cup smooth peanut butter

1 teaspoon vanilla

1/4 cup milk

4 cups powdered sugar

7 oz jar marshmallow creme

Preparation

  1. Preheat oven to 350. Line 24 muffin tins with cupcake liners.
  2. In a large mixing bowl, combine cake mix, water, peanut butter, vegetable oil, eggs and vanilla. Beat on low speed for about a minute. Increase speed to medium and beat for 2 minutes more, scraping sides of bowl as needed. Fill liners 2/3 full and bake for 15 - 20 minutes or until tops spring back when lightly touched. Remove cupcakes from pan and cool on cooling rack.
  3. Once cupcakes are completely cool, prepare frosting: In a large mixing bowl, beat butter, peanut butter, vanilla, and milk on medium-low speed until smooth. Slowly add powdered sugar, beating on low until just barely mixed in. Increase speed to medium high and beat for about 2 minutes. Using a rubber spatula, barely fold in marshmallow creme (you don’t want it mixed completely in…you want to see swirls).
  4. Pipe frosting or frost with a spatula generously.