Cut a square of parchment, wax paper or aluminum foil to line a 9x5x5 inch loaf pan with enough to extend over the edges by 2 inches. Spray inside with Pam or brush with butter or oil.
Butter the sides of a heavy medium saucepan. Mix sugar, cream, chocolate, Karo syrup and salt, stirring over high heat until boiling. Reduce heat to a slow boil (medium-low). Cook, uncovered, stirring occasionally for 10-15 minutes until candy thermometer reads 236F or the soft-ball stage, adjusting burner as needed to regulate temperature.
Remove from heat; add butter, and vanilla without stirring. Do not stir; set aside to cool for an hour or until mixture is 110F degrees.
Beat with a wooden spoon or electric mixer until fudge becomes dull and is no longer glossy. Fudge will become thick when ready. Stir in nuts.
Spread in pan evenly. Mark squares using a fork (do not cut) while still warm. If desired, extra chopped nuts may be sprinkled over and pressed lightly into the top.
Refrigerate.
After the fudge sets up, lift it from the pan and cut into squares using a knife dipped into hot water.
Keep in a cool, dry place.
Variation: 1/2 cup minced raisins soaked in 1 tablespoon of rum may be added with or instead of the raisins.
Submitted by: CM
