Midnight Bars

1/4 lb. butter, at room temperature or cut in thin pats 1 c. sugar 1/2 c. dutch-process cocoa 2 large eggs 1/2 c. all purpose flour 1 c. coarsely chopped walnuts With an electric beater cream butter, sugar and cocoa; at high speed, beat in eggs, one at a time. Add flour; beat gently to blend. Stir in walnuts. Turn into a buttered 8x8x2" baking pan. Bake in 350F oven until sides shrink from pan, about 25 min. A cake tester inserted in center will not come out clean. Cool on wire rack. Chill before cutting into bars and removing with a small metal spatula.