Makes 2 dozen sandwiches
3 1/2 cups all-purpose flour
1 teaspoon salt
1 1/2 cups unsweetened cocoa powder
1 tablespoon baking soda
1 teaspoon baking powder
1 cup (2 sticks) unsalted butter, room temperature
2 cups sugar
2 large eggs
2 cups buttermilk, room temperature
2 teaspoons pure vanilla extract
Seven Minute Frosting
1. Preheat oven to 400 degrees. Sift together flour, salt, cocoa powder, baking soda, and baking powder. Set aside. Line two baking pans with Silpats (French nonstick baking mats) or parchment paper. In the bowl of an electric mixer fitted with the paddle attachment, cream butter and sugar until light and fluffy. Add eggs, buttermilk, and vanilla. Beat until well combined. Slowly add dry ingredients. Mix until combined.
2. Using a 1-ounce ice-cream scoop, place cookies onto lined baking pans, twelve per pan. Bake for 12 minutes. Remove to a rack to cool. Repeat with remaining batter.
3. Spread 2 tablespoons of frosting onto each of twenty-four of cookies. Sandwich together with remaining twenty-four cookies. Store in an airtight container for up to 3 days.
