4 sq. unsweetened chocolate
3/4 c. (1 1/2 sticks) butter
2 c. sugar
3 eggs
1 tsp. vanilla
1 c. all-purpose flour
1 c. walnuts, chopped (optional)

Microwave chocolate and butter in a large bowl on High 2 minutes or until melted. Stir until chocolate is completely melted. Stir sugar into chocolate. Mix in eggs and vanilla. Stir in flour and nuts. Spread into a greased 9 x 13-inch pan and bake at 350°F for 30 to 35 minutes.