Pumpkin Marshmallow & Spice Fudge

Using foil, line a 13 x 9-inch baking pan; set aside. (There is no need to grease the foil.) In heavy 4-quart saucepan, mix together both sugars and pumpkin spice; add the cream, pumpkin puree, stirring until combine; then add the butter and cook over medium heat, stirring constantly, until mixture comes to full rolling boil; continue cooking, without stirring, until mixture reaches 234°F on candy thermometer***, about 7 to 8 minutes, or until a small amount of candy mixture dropped into very cold water forms a soft ball which flattens when removed from water. Remove from heat and quickly stir in the white chocolate chips, marshmallow creme, pecans (if using) and vanilla extract, stirring until the chips and marshmallow creme are completely melted. Immediately pour into the foil-lined pan and spread quickly. Let stand at room temperature until completely cooled and firm, about 2 to 3 hours. Lift fudge from pan, carefully remove the foil and cut into 1-inch squares. Makes about 3 pounds or 48 (1-inch) servings.