Mississippi Mud Bars 1/2 cup margarine 1/4 cup firmly packed brown sugar 1 egg 1 teaspoon vanilla 1 cup flour 1/2 teaspoon baking soda 1/4 teaspoon salt 8 squares simi sweet chocolate, chopped 6 squares white chocolate, chopped 1 cup chopped walnuts Beat margarine, sugar, egg and vanilla until light and fluffy. mix in flour, baking soda and salt. Stir in 1/2 of the semi sweet, and 1/2 the white chocolate, and 1/2 cup walnuts. Spread into a lightly greased 9 inch square baking dish. Bake in a 350 degree oven for about 25 minutes or until toothpick comes out clean sprinkle with remaining chocolate. Cover with foil until chocolate has melted Sprinkle with rest of walnuts. cool then cut into bars.