How to Make White Chocolate Fudge

Gather the ingredients. Prepare a 9x9-inch pan by lining it with aluminum foil and spraying the foil with nonstick cooking spray. Place the cubed butter in a heavy bottomed 4-quart saucepan over low heat, and stir it occasionally until it is nearly melted. Add the sour cream, sugar, and salt, and raise the heat to medium. Stir until the sugar melts. Continue to cook the fudge, stirring frequently, until it comes to a boil. Insert a candy thermometer and cook the fudge, stirring frequently, until it reads 235 F/113 C on the candy thermometer. Once it reaches 235 F, remove the pan from the heat and add the white chocolate chips and the marshmallow cream. Stir vigorously until they melt into the fudge. If necessary, return the fudge to the heat for brief periods to melt the chips. Add the vanilla and stir well. Pour the fudge into the prepared pan and smooth it into an even layer. Allow it to set at room temperature for 3 to 4 hours, or in the refrigerator for 1 to 2 hours. Serve and enjoy!