Line an 8 inch square pan with aluminum foil or parchment paper, Butter foil to make sure the fudge releases easily.
Place the 3/4 cup eggnog, butter and sugar in a medium size saucepan. Heat over medium heat stirring frequently. Keep heating and stirring until the mixture reaches a full boil.
1/2 cup butter, 3/4 cup eggnog, 2 cups sugar
Allow it to simmer with a slow rolling boil until a candy thermometer reads 23 (soft ball stage). Remove the pan from the stove top.
Add in white chocolate chips, marshmallow creme, vanilla, and ½ tsp nutmeg. Stir until the chocolate chips have melted completely and all of the ingredients are well incorporated.
2 1/2 cups white chocolate chips, 7 ounce marshmallow fluff, 1 tsp ground nutmeg, 2 tsp vanilla extract
Pour the creamy eggnog fudge mixture into the bottom of the pan. Smooth it out with a rubber spatula if needed.
Sprinkle the top of the fudge evenly with ½ tsp of nutmeg.
Place in the refrigerator for at least 4 hours or until completely set.