In a mixing bowl, cream butter and sugar. Add eggs and vanilla; mix well. Stir in applesauce. Combine flour, baking soda and spices; stir into creamed mixture. Fold in nuts. Fill greased or paper-lined muffin cups three-fourths full. Bake at 350° for 25 minutes or until muffins test done. Sprinkle with cinnamon-sugar if desired.