1/2 cup (1/4 lb.) butter
3 ounces unsweetened chocolate, chopped
1 1/3 cups sugar
2 large eggs
1 teaspoon vanilla
1/2 cup all-purpose flour
1/2 cup chopped walnuts
1. In a 2- to 3-quart pan over low heat, frequently stir butter and chocolate until melted and smooth. Remove from heat and stir in sugar, eggs, vanilla, flour, and walnuts until well blended.
2. Spread batter evenly in a buttered and floured 8-inch square baking pan.
3. Bake in a 350° oven until edges feel firm to touch and begin to turn a shade darker, 25 to 30 minutes.
4. Run a knife between pan rim and brownie. If desired, spread with chocolate glaze. Let cool in pan on a rack, about 1 hour. Cut into 9 or 16 squares.