Beat together butter and shortening; gradually add sugars, creaming until mixture is light and fluffy. Beat in eggs one at a time.
Sift together dry ingredients; add alternately with milk and vanilla to the creamed mixture. Stir in nuts.
Pour batter into greased and floured 10" tube pan. Bake in moderate oven (350°) 1 hour and 15 minutes, or until done when tested with a straw. Cool on rack 10 minutes, then remove from pan and place on rack over a piece of waxed paper. Pour Walnut Glaze over hot cake. If icing falls onto the waxed paper, scoop it up and put it back on the cake.