Step 1Spread shortening on the bottom and sides of a (9-inch-square) baking pan. Heat the oven to 350 degrees.
Step 2Sift together the flour, baking powder, baking soda and salt. Set aside.
Step 3In the large bowl of an electric mixer, cream together the butter and sugar until well blended. Add the eggs, one at a time, beating after each addition. Alternately add the dry ingredients and the mashed bananas to the batter, beating slowly after each addition. Stir in the nuts, chocolate chips and wheat germ if used. Spoon the batter into the pan, smooth the top evenly, then spread the batter slightly toward the pan edges.
Step 4Bake until a cake tester inserted in the center comes out clean and the cake is lightly springy to the touch, 30 to 35 minutes. Cut into squares to serve.