Pumpkin Pie Fudge

3 c. sugar
3/4 c. unsalted butter, melted
2/3 c. evaporated milk
1 c. canned pumpkin puree
2 tbsp. corn syrup
2 1/2 tsp. pumpkin pie spice
9 oz. white chocolate, chopped
7 oz. jar marshmallow creme
1 c. walnuts, chopped and toasted
1 tsp. vanilla extract

Stir together first 6 ingredients in a 3 1/2-quart saucepan over medium-high heat and cook, stirring constantly, until a candy thermometer registers 234°F (soft-ball stage).

Remove pan from heat; stir in remaining ingredients until well-blended. Pour into a greased aluminum foil-lined 8-inch square pan. Let stand 2 hours or until completely cool; cut fudge into squares.