In a bowl, beat the egg. Gradually beat in brown sugar and shortening. Combine flour, baking powder, baking soda and salt; add to egg mixture alternately with buttermilk. Beat just until moistened. Stir in nuts. Pour into a greased 9x5-in. loaf pan. Bake at 350° for 45-55 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes; remove from pan to a wire rack.