Beat egg yolks. Add sugar gradually and beat 10 minutes. Add flour and mix, add nuts and blend in rum. Beat egg whites until stiff and fold gently into batter. Pour into greased and floured cookie sheet. Bake at 350 degrees for 35-40 minutes.
For icing: Cream butter, margarine and powdered sugar. Add remaining ingredients. Frost torte and sprinkle with chopped nuts. Torte can be cut in squares and served. Or, cut in 3 layers and then frost each layer and outside of torte.