01 - Line an 8x8-inch baking pan with parchment paper, leaving an overhang for effortless removal.
02 - In a medium saucepan over medium heat, combine unsalted butter, eggnog, and granulated sugar. Stir frequently until the mixture reaches a gentle boil.
03 - Reduce heat to low and simmer for 4–5 minutes, stirring constantly to prevent scorching.
04 - Remove pan from heat. Add white chocolate chips, ground nutmeg, ground cinnamon, and pure vanilla extract. Stir until chocolate is completely melted and mixture is smooth.
05 - Immediately transfer fudge mixture into the prepared pan. Smooth the surface with a spatula. Sprinkle freshly grated nutmeg over the top if desired.
06 - Allow to cool at room temperature for 30 minutes, then refrigerate for at least 2 hours or until firmly set.
07 - Using the parchment overhang, lift fudge from the pan. Cut into 36 squares with a sharp knife.