1/4 cup packed brown sugar 1 teaspoon ground cinnamon 1/3 cup finely chopped walnuts 1 cup stirred whole wheat flour 3/4 cup sifted all-purpose flour 1 teaspoon baking soda 1/2 teaspoon salt 2/3 cup shortening 1/2 cup packed brown sugar 2 eggs 1 teaspoon vanilla extract 1 cup very ripe mashed banana 1/4 cup milk
Combine 1/4 cup brown sugar, cinnamon and walnuts in bowl. Mix well. Set aside.
Stir together whole wheat flour, all purpose flour, baking soda and salt. Set aside. Cream together shortening and 1/2 cup brown sugar in bowl, using an electric mixer at medium speed. Beat in eggs, vanilla and banana. Gradually add flour mixture alternately with milk, beating well after each addition. Pour batter into greased 8-inch square glass baking dish, spreading batter slightly higher in corners. Sprinkle evenly with walnut mixture.
Microwave (Medium setting) 9 minutes, rotating dish one quarter turn every 2 minutes. Place small pieces of aluminum foil over cooked areas of cake. Check the use and care manual for your microwave oven before using foil, because the magnetron tubes on some ovens can be damaged by foil. Microwave (High setting) 4 to 5 minutes, or until cake pulls away from sides of dish and top is done. Cool in dish on wooden board or heatproof surface. Serve warm or cool.