Yield: 2 pounds
Line a 9-in. square pan with foil. Grease the foil with 1½ teaspoons butter; set aside. In a heavy saucepan, combine the sugar, sour cream, and remaining butter. Cook and stir over medium heat until sugar is dissolved. Bring to a rapid boil; cook and stir until a candy thermometer reads 234 degrees (soft-ball stage), about 5 minutes.
Remove from the heat; stir in white chocolate and marshmallow creme until melted. Fold in peppermint candy and extract. Pour into prepard [sic] pan. Chill until firm. Using foil, lift fudge out of pan. Gently peel off foil; cut fudge into 1-in. squares. Store in the refrigerator.