In a mixing bowl, cream the butter and 1 cup sugar. Add eggs, one at a time, beating well after each addition. Stir in apple. Combine the flour, baking soda and salt; add to creamed mixture alternately with buttermilk.
Stir in vanilla and nuts. Pour into a greased and floured 9x5x3-inch loaf pan. Combine cinnamon and remaining sugar; sprinkle over batter.
Bake at 350° F or 60-65 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes; remove from pan to a wire rack.Servings: 1 loaf