Ingredients: For the Cookies: 2/3 cup unsalted butter, softened 1/2 cup granulated sugar 1/4 cup powdered sugar 1 teaspoon baking powder 1 large egg 1 teaspoon vanilla extract 1 1/2 cups all-purpose flour For the Royal Icing: 2 cups powdered sugar, sifted 1 teaspoon vanilla extr…