Cream together shortening and sugar, add eggs and beat well. Sift dry ingredients, add to creamed mixture alternately with banana, blending well after each addition. Stir in nuts. Pour into well-greased 4 to 6 cup mold. Cover with foil and tie. Pour 2 cups hot water in slow cooker. Place mold on rack or trivet in pot. Cover and cook on high 2 to 3 hours or until bread is done. Serve warm or cool, with butter or cream cheese or peanut butter.