1/2 c. (1 stick) butter
2 oz. unsweetened chocolate
1 c. sugar
1/2 c. all purpose flour
1/2 tsp. baking powder
2 eggs
1 tsp. vanilla
1/2 c. chopped walnuts

Preheat oven to 450 degrees. Grease an 8 inch square baking pan. Melt butter with chocolate in medium sauce pan. Remove from heat. Combine sugar, flour and baking powder in large bowl. Add eggs and vanilla and beat well. Pour in chocolate mixture and blend thoroughly. Stir in walnuts. Pour into pan. Bake until tester inserted in center comes out clean, about 15 to 20 minutes. Cool completely in pan before cutting into squares.