4 squares baking chocolate, unsweetened
3/4 cup (1-1/2 sticks) butter or margarine
2 cups sugar
3 eggs
1 tsp vanilla
1 cup flour
1 pkg (8 oz) baking chocolate squares, semi-sweet, coarsely chopped
1 cup nuts, coarsely chopped (optional)
1/2 cup raisins (optional)