Melt and set aside:

9 oz. butter
8 1/2 oz. unsweetened chocolate

In mixer bowl, beat until just combined:

7 eggs
6 cups + 3 T. sugar
1 tsp. vanilla

Add melted chocolate and butter

Add:

2 cups + 5 T. flour
1 tsp. salt
1 1/6 tsp. baking soda

Pour into greased and parchment lined 12 by 16 in. sheet pan.

Variations:

Swirl in some cream cheese frosting.
Add chocolate chips to batter.
When cool, spread with raspberry jam and then top with fudge frosting.
Add nuts of choice for top or mixed in with batter.