By hand, lightly cream butter with sugar.
Mix in eggs, vanilla and salt.
Melt chocolate according to package directions.
Stir melted chocolate into creamed mixture.
Add flour, mixing until smooth; add nuts.
Spread into greased 8 or 9-inch square pan.
Bake at 350°F for 20-25 minutes.
For extrafudgy brownies, use 8-inch pan or less baking time.
For cakelike brownies, use 9-inch pan or longer baking time.
Cool in pan.
Frost with half recipe Dark Chocolate Frosting.
Cut into squares.