Ingredients

  • 1 cup brown rice flour
  • 1 cup millet flour
  • 1/2 cup potato starch
  • 1/2 cup cocoa powder, unsweetened
  • 1 1/2 teaspoons xanthan gum
  • 1 teaspoon baking soda
  • 1/2 teaspoon salt
  • 1/2 cup unsalted butter, room temperature
  • 1 cup brown sugar, packed
  • 1 egg
  • 1 teaspoon vanilla extract
  • 1 cup milk
  • 1 cup unsalted butter, room temperature
  • 2 cups marshmallow cream
  • 1/2 teaspoon pure peppermint extract
  • 1 1/2 cups powdered sugar
  • red food coloring (however much you like)

Method

  • Preheat oven to 350 degrees. Line baking sheets with parchment paper. Whisk together flours, potato starch, cocoa, xanthan gum, baking soda, and salt in a bowl; set aside. Cream butter and brown sugar together in a large bowl with a hand mixer on medium speed until light and fluffy. Beat in egg and vanilla until combined. Alternately add flour mixture and milk into the beaten ingredients, beating just until combined. Scoop batter onto prepared baking sheets in 2 tablespoon portions. Bake whoopies until edges are set and they spring back when touched, 10-12 minutes. Remove whoopies from oven, let cool on baking sheets for 5 minutes, then transfer to a cooling rack. Cool completely before filling.
  • For filling, cream butter in a bowl with hand mixer on medium speed. Beat in marshmallow cream, mint extract, and red food coloring. Add powdered sugar in stages, beating slowly to incorporate, and then kicking speed up to high to fluff the filling.
  • Pipe 2 tablespoons peppermint filling onto one whoopie, and place another whoopie on top.