In a high-speed blender, pour in the eggnog, followed by the vanilla ice cream, freshly grated nutmeg, ground cinnamon, vanilla extract, and a pinch of sea salt.
Blend the mixture on high speed for about 30-45 seconds, or until it reaches a silky smooth and creamy consistency.
Take a moment to taste the shake; if you desire more sweetness, add a little extra eggnog or a scoop of ice cream to suit your palate.
Carefully pour the velvety milkshake into pre-chilled glasses to keep the drink cool and refreshing.
Generously crown each milkshake with a cloud of whipped cream, and finish with a sprinkle of additional freshly grated nutmeg for an elegant touch.
Serve immediately with festive straws or a dash of ground cinnamon to celebrate the joyous season.
Notes
For a sweeter shake, adjust the eggnog or ice cream to taste.