INGREDIENTS For the cookies 1/2 cup unsalted butter, room temperature 1 cup granulated sugar 1 egg, room temperature 2 teaspoons vanilla extract 1/4 cup sour cream 2 cups flour 1/2 teaspoon baking powder 1/4 teaspoon baking soda 1/2 teaspoon salt For The Frosting 3 cups powdered sugar 3 to 4 tablespoons milk 2 tablespoon corn syrup 1 teaspoon vanilla extract 1/2 teaspoon salt 3 Tablespoons cocoa powder INSTRUCTIONS https://bromabakery.com/black-and-white-cookies/