Chop walnuts fine. Peel and mash bananas (should measure one cup pulp.) Resift flour with baking powder, soda, salt and sugar into mixing bowl.Add the cup banana pulp, shortening, milk and vanilla. Beat 2 minutes on mixer set at medium speed.
Scrape bowl often.Add eggs and beat 2 minutes longer. Stir in nuts. Turn batter into greased and floured 13 x 9 x 2 inch loaf pan; spread evenly. Bake in moderate oven (350 F) until cake tests done, about 35 minutes. Remove from oven and let cool in pan. Serve plain or frost top of cooled cake with lemon butter icing. Sprinkle top with additional chopped black walnuts, if desired. Makes one large loaf.
Lemon Butter Icing:
Beat 1/4 cup soft butter, 3 cups confectioner sugar, 2 tbsp cream and 1 tbsp lemon juice until fluffy. If you like a stronger lemon flavor add 1/2 tspn grated lemon peel.