4 cups sugar
1 1/3 cups milk or half-and-half
1/4 cup corn syrup
1/4 teaspoon salt
4 oz unsweetened baking chocolate or 2/3 cup unsweetened baking cocoa
1/4 cup butter or margarine
2 teaspoons vanilla
1 cup coarsely chopped nuts, if desired
1. Grease bottom and sides of 8-inch square pan with butter.
2. In 3-quart saucepan, cook sugar, milk, corn syrup, salt and chocolate over medium heat, stirring constantly, until chocolate is melted and sugar is dissolved. Cook, stirring occasionally, to 234°F on candy thermometer or until small amount of mixture dropped into cup of very cold water forms a soft ball that flattens when removed from water; remove from heat. Stir in butter.
3. Cool mixture without stirring to 120°F, about 1 hour. (Bottom of saucepan will be lukewarm.) Add vanilla. Beat vigorously and continuously 5 to 10 minutes, using wooden spoon, until mixture is thick and no longer glossy. (Mixture will hold its shape when dropped from a spoon.)
4. Quickly stir in nuts. Spread in pan. Let stand about 1 hour or until firm. Cut into 1-inch squares.