2 (14 oz.) cans sweetened condensed milk
4 (1 oz.) squares unsweetened chocolate
1/4 c. butter
Dash of salt
1 tsp. vanilla extract

Combine all ingredients in a heavy saucepan. Cook over low heat, stirring constantly with a wire whisk until chocolate melts and mixture is smooth. Serve warm over ice cream. Yields 3 1/3 cups.