butter, softened (room temperature) • granulated sugar • egg, beaten (room temperature) • granny smith apples, cored, peeled & diced (2 cups; 2 apples is probably enough) • ⁄4 cup chopped walnuts • vanilla extract • baking soda • baking powder • salt • ground cinnamon • ground nutmeg (this is a bit much for my taste) • all purpose flour