Preheat oven to 300 F. Line cookie sheet with parchment paper or non-stick baking mat.
In a medium bowl, combine flour, baking powder, cinnamon and the ½ tsp of nutmeg. Set aside.
Using the paddle attachment on a mixer, cream the sugar and butter to form a grainy paste.
Add eggnog, vanilla and egg yolks and continue beating until smooth.
Add the flour mixture and beat just until combined, making sure not to overmix. The dough may seem a little “wetter” than a typical drop cookie dough.
Drop rounded teaspoon on to baking sheets. Flatten the tops slightly and dust lightly with nutmeg.
Bake 22-25 minutes or until the bottoms turn brown.
Transfer to a cooling rack immediately, allow to cool, and enjoy!