– 3/4 cup butter -- 1/2 cup granulated sugar – 1/2 cup light brown sugar – 1 egg + 1 egg yolk – 2 cups all purpose flour – 1 teaspoon salt – 1/2 teaspoon baking soda – 1/2 cup white chocolate chips – 1/2 cup semi-sweet chocolate chips – 3/4 cup Christmas M&M's