Ingredients 2 cups + 2 tablespoons all-purpose flour ¾ teaspoon baking powder ½ teaspoon fine sea salt ¼ teaspoon baking soda ¾ cup unsalted butter, room temp 1 & ½ cups granulated sugar 6 large egg whites, room temp ¾ cup whole milk, room temp 1 tablespoon vanilla extract ½ cup sour cream, room temp ¾ cup patriotic sprinkles For the frosting: ¾ cup unsalted butter, softened 3 cups powdered sugar Pinch of sea salt 2 tablespoons whole milk 1 teaspoon vanilla extract More sprinkles for garnish, optional