INGREDIENTS:
8 oz unsweetened chocolate (8 squares) 
1/2 lb butter 
5 eggs 
2 1/2 cups sugar 
1 Tbsp vanilla extract 
1 1/2 cups flour 
2 cups coarsely chopped walnuts  

DIRECTIONS:
Grease a 13x9 inch pan and pre-heat oven to 375 deg. F. 
Melt the chocolate and the butter in the top of a double  boiler over simmering water. Whisk until smooth. 
Set aside to cool while beating eggs. 
Beat the eggs, sugar and vanilla at high speed for a full 10 minutes. 
Blend in the chocolate-and-butter mixture at low speed. 
Add flour, beating just to blend.
Stir in walnuts, if desired. 
Bake 30 to 35 minutes.
Do not overbake.
The brownies are done when a toothpick inserted into the center comes out slightly dirty. 
Cool in pan, then cut into squares.