Killer Brownies

Because no one should talk about killer brownie recipes without sharing--
Melt 1 stick of butter with 2 squares of unsweetened chocolate. Stir in 1 c. sugar; add 2 eggs and 1/2 t. vanilla. Beat well. Stir in 1/4 c. all-purpose flour and 1/2 t. salt. If you like, add 1 c. chopped walnuts. Bake in a buttered and floured 8-inch square pan for about 40 minutes at 325. Laurie Colwin says this is Katharine Hepburn's recipe. I had hunted high and low for a good brownie recipe, and this is it.