PREPARATION:

1. Butter 8-inch square pan; set aside. Lightly butter side of heavy, large saucepan.
2. Combine granulated sugar, whipping cream, brown sugar and corn syrup in prepared saucepan. Cook over medium heat, stirring constantly, until sugar dissolves and mixture comes to a boil. Add candy thermometer. Stir mixture occasionally. Continue to cook until mixture reaches soft-ball stage (238°F).
3. Remove from heat. Slice butter into thin slices and place on top of cooling mixture. Let stand about 10 minutes. Add white chocolate chips and nuts. Stir until butter and chips are completely melted. Spread into prepared pan. Refrigerate until firm. Cut into squares. Store in refrigerator.