Banana-fudge Walnut Brownies

Heat oven to 350. Grease bottom ONLY of 8-inch square pan.

Melt in 2-quart saucepan, over low heat, stirring constantly; 1/2
stick butter (1/4 cup) 1 pkg. (6 oz.) semi-sweet chocolate
chips Beat in thoroughly with spoon; 3/4 cup all-purpose flour 1/2
teaspoon vanilla 1/2 cup sugar 1/4 teaspoon baking powder 1/3 cup
chopped walnuts 1/4 teaspoon salt 1/3 cup mashed ripe banana 1 egg
(about 1 small) Spread batter evenly in pan. Bake about 30 minutes or
until center is set. Cut into 2-inch squares.