Line a loaf pan (about 9x5-inches) or small square pan with parchment paper, allowing paper to hang halfway over the sides of the pan. 

In the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl, add the marshmallow cream, chopped white chocolate, and 1/2 teaspoon Buttered Popcorn Flavor. Mix together until just combined and set aside. 

In a heavy, 2-quart saucepan melt the butter over low heat. Stir in the granulated sugar, and whipping cream until combined. Increase heat to medium and bring mixture to a boil WITHOUT STIRRING. As soon as mixture comes to a boil, wash down the sides of the pan with a wet pastry brush to remove any stray sugar crystals clinging to the side of the pan. Clip on a candy thermometer and continue to cook, WITHOUT STIRRING, to 240° F. Remove from heat and allow to cool until no longer boiling. 

Pour the hot mixture into the bowl that contains the marshmallow cream mixture and stir until well combined. 

Using a spatula, transfer candy to the lined pan and spread to smooth. Once firm, cut fudge into slabs or pieces. 

To store, wrap fudge in waxed paper and place in an airtight container; refrigerate up to 3 weeks. To freeze, wrap fudge in waxed paper, then foil and place in an airtight container. Can be frozen for several months. 

Makes about 2 pounds of fudge