Red Velvet Whoopie Pies

Ingredients

• 2 cups all-purpose flour
• 1/2 cup unsweetened cocoa powder
• 1 teaspoon baking soda
• ¼ teaspoon salt
• 8 tablespoons (1 stick) unsalted butter, at room temperature
• 1 cup granulated sugar
• 1 large egg
• 2 tablespoons red food coloring
• 1 1/2 teaspoons vanilla extract
• 1 cup buttermilk
• 1 1/2 cups confectioners’ sugar
• One 7-ounce container marshmallow creme
• 4 ounces cream cheese, at room temperature
• 2 tablespoons unsalted butter, at room temperature
• 1 teaspoon vanilla extract