Banana Fudge-Walnut Brownies
["1/4 c. (1 stick) margarine or butter", "1 (6 oz.) pkg. semi-sweet chocolate chips", "3/4 c. unbleached flour", "1/2 c. sugar", "1/3 c. chopped walnuts", "1/3 c. mashed, ripe banana (about 1 small)", "1/2 tsp. vanilla", "1/4 tsp. baking powder", "1/4 tsp. salt", "1 egg"]
["Heat oven to 350\u00b0.", "Grease bottom only of an 8-inch square pan.", "Melt in a 2 quart saucepan over low heat, stirring occasionally, the margarine and chocolate chips.", "Beat in thoroughly with a spoon the flour, sugar, chopped walnuts, banana, vanilla, baking powder, salt and 1 egg.", "Spread batter evenly in pan.", "Bake about 30 minutes or until center is set.", "Cool completely.", "Cut into 2-inch squares."]
["margarine", "semi-sweet chocolate chips", "flour", "sugar", "walnuts", "banana", "vanilla", "baking powder", "salt", "egg"]