1. Do NOT preheat oven.
2. Beat butter and shortening ustil smooth and creamy. Add sugar and beat at medium speed for 5 minutes. Add eggs, one at a time and beat until well blended.
3. In a small bowl combine the flour with the baking soda. Add slowly into the butter/sugar mixture, alternately with the milk until just blended.
4. Stir in vanilla. Fold in the chopped walnuts and pour into a greased, floured 10-inch tube pan or bundt pan.
5. Place in a cold oven and bake at 325 degrees for 1 1/4 or 1 1/2 hours until done. Test for doneness with a toothpick. Cool in pan for 30 minutes. Remove from pan and continue to cool on a rack or turn out on a cake plate. Glaze if desired.