Sour Cream Fudge with Walnuts

Combine sugar, sour cream, milk, corn syrup, and butter in a heavy-bottomed saucepan. Stir over medium heat until the sugar dissolves completely and the mixture begins to boil.

Once boiling, stop stirring and insert a candy thermometer. Continue cooking without stirring until the mixture reaches 238°F (soft-ball stage).

Remove the saucepan from heat and place it on a cool surface. Allow the mixture to cool to approximately 110°F without stirring.

Stir in the vanilla extract and beat the mixture vigorously with a wooden spoon until it loses its glossy appearance and becomes thick and grainy, about 2–3 minutes.

Quickly fold in the walnut halves if using, distributing them evenly throughout the fudge.

Pour or spoon the fudge onto a buttered or parchment-lined 8-inch square pan, pressing it evenly into the corners.

Allow the fudge to set at room temperature for at least 2 hours, or until firm enough to cut cleanly into 1-inch squares.