Gluten-Free Whoopie Pies

• 1 cup white rice flour
• 1/2 cup sweet rice flour
• 1/2 cup Dutch-process cocoa powder
• 1/2 cup tapioca starch
• 1 1/4 teaspoons baking soda
• 1 teaspoon salt
• 1/2 teaspoon xanthan gum
• 1/2 cup (8 tablespoons) unsalted butter, at room temperature
• 1 cup packed dark brown sugar
• 1 large egg
• 1 teaspoon pure vanilla extract
• 1 cup buttermilk
• Cream Filling (recipe follows)
• 1/2 cup (8 tablespoons) unsalted butter, at room temperature
• 1/4 cup vegetable shortening
• 3/4 cup powdered sugar
• 1 jar (7 1/2 ounces) marshmallow creme
• 1 teaspoon pure vanilla extract

1. In a medium bowl, cream together the butter and vegetable shortening until light and fluffy. (Use high speed on a handheld mixer or medium-high speed on a stand mixer.) Add the powdered sugar and beat until combined. Add the marshmallow creme and vanilla extract. Mix until fluffy.
2. Adjust oven rack to the middle position and preheat the oven to 350u0b0F. Line an 18 by 13-inch baking sheet with parchment paper.
3. In a small bowl, whisk together the dry ingredients.
4. In a large bowl, beat together the butter and brown sugar until the butter-sugar paste lightens slightly, about 1 minute on medium-high speed in a stand mixer or high speed with a handheld mixer. Add the egg and vanilla extract and mix for 1 minute. Turn off the mixer and scrape sides and bottom of bowl.
5. Add half of the dry ingredients. Mix until combined. Add half of the buttermilk. Mix until smooth. Add the remaining dry ingredients. Mix until combined. Add the remaining buttermilk. Mix the batter for 30 seconds.
6. Scoop six 1/4-cup mounds of batter onto the baking sheet. Be sure to space batter several inches apart, as the cakes will spread during baking.
7. Bake for 15 to 18 minutes, until the cakes are set and spring back to the touch.
8. Remove from the oven and place on a wire rack. Allow the cakes to cool on the pan for 2 minutes. Transfer the warm cakes to the wire rack to cool completely.
9. Repeat with the remaining batter. As the cakes cool, make the cream filling.
10. When the cakes are all completely cooled, sandwich them together with the filling. (If the cakes are too warm, the filling will melt. Be sure to wait until the cakes are completely cool.) Wrap tightly with plastic wrap and store at room temperature for up to 3 days. These pies don't freeze well.

white rice flour, sweet rice flour, dutch, tapioca starch, baking soda, salt, xanthan gum, unsalted butter, brown sugar, egg, vanilla, buttermilk, cream filling, unsalted butter, vegetable shortening, powdered sugar, marshmallow creme, vanilla

Taken from www.seriouseats.com/recipes/2012/06/gluten-free-whoopie-pies.html (may not work)