1. Grease well a 12-cup fluted tube pan, or 10-inch angel cake tube pant
2. Beat butter or margarine in large bowl of electric mixer at high speed until creamy; beat in eggs, one at a time, until well blended; gradually beat in sugar until fluffy.
3. Stir in flour and 3 1/3 cups of dry frosting mix and walnuts into batter with wooden spoon until well blended; pour into tube pan.
4. Bake in moderate oven (350°) 1 hour, or until top is dry and shiny. (Because the frosting mix has made a soft tunnel in center of cake, it i$ impossible to test the cake, using standard tests.)
5. Cool cake in pan on wire rack 1 hour; loosen cake around edge and tube; invert onto wire rack; cool.
6. Stir a few drops water into remaining frosting mix in a small bowl; spoon over cake just before serving.