Preheat oven to 350�F. Butter a 9 x 9 x 2-inch baking pan. In a small bow, mix flour, baking soda and salt; set aside. In a large mixer bowl at medium speed, heat peanut butter and butter or margarine until well blended. Gradually beat in brown sugar and sugar until light and fluffy. Add eggs, one at a time, and beat well after each addition. Beat in banana, vanilla and lemon juice. Add dry ingredients and beat just until blended. Stir in nuts and chips. Spread in baking pan. Bake for 35 to 40 minutes or until cake pulls away from pan. Cool pan on a wire rack Cover with plastic wrap. Serve the next day. Sprinkle with powdered sugar if desired.

Makes 16 squares.