Cream butter and shortening. Add sugar and beat until very light. Add eggs, one at a time, beating well. Add flavoring and beat again. Add flour mixed with baking powder, alternating with milk, starting and ending with flour. Fold in walnuts.
Pour into a tube pan that has been greased and floured. Use one very large pan, size 4 3/4 x 9 1/2 inches. Bake for 80 minutes. Or use two regular pans, size 3 1/2 x 9 inches and bake for 70 minutes. Bake at 325 degrees.

Do not open oven during first hour.