4 (1 oz) unsweetened chocolate squares
1 cup butter or margarine
2 cups sugar
4 large eggs
1 cup all purpose flour
1/8 tsp salt
2 tsp vanilla extract
2 cups (12 oz) semisweet chocolate morsels
2 cups mini marshmallows
Heat chocolate and butter in large saucepan over medium heat, stirring constantly until melted. Stir in sugar and cook, stirring constantly, until sugar melts. Cool 15 minutes.
Add eggs and stir until blended. Add flour, salt, and vanilla, stirring until blended. Stir in chocolate morsels and marshmallows and pour into greased 9 x 13-inch pan.
Bake at 350 for 30 to 35 minutes. Cool in pan on wire rack. Cover and let stand at room temperature 8 hours. They are best if you let them stand overnight.