2 cups sugar
2/3 cup milk
2 ounces unsweetened chocolate
2 tablespoons corn syrup
1/4 teaspoon salt
1 teaspoon vanilla
2/3 cup coarsely chopped nuts (opt)
Butter 9 inch by 5 inch by 3 inch loaf pan. Combine sugar, milk, chocolate, corn syrup and salt in 2 quart saucepan. Cook over medium heat, stirring constantly, until chocolate is melted and sugar is dissolved. Cook, stirring occasionally, to 234 degrees on candy thermometer (or until small amount of mixture dropped into very cold water forms a soft ball which flattens when removed from water).
Remove from heat. Add butter. Cool mixture to 120 degrees without stirring. (Bottom of pan will be lukewarm.) Add vanilla. Beat vigorously and continuously 50 to 10 minutes with wooden spoon, until candy is thick and no longer glossy. (Mixture will hold its shape when dropped from spoon.) Quickly stir in nuts. Spread mixture evenly in buttered pan. Cool until firm. Cut into squares.