Preheat oven to 350°F

In the bowl of a stand mixer with the paddle attached, beat together butter and both sugars until fluffy, about 3-5 minutes.

Add eggs one at a time, beating just until combined.

Mix in vanilla extract.

In a separate bowl, whisk together flour, baking powder, salt, and nutmeg.

Alternately add flour mixture and eggnog to batter, mixing after each addition until just combined.

Scoop dough by heaping tablespoonfuls onto parchment paper-lined baking sheets, spacing cookies 2-inches apart.

Bake for 11-13 minutes.

Rest on baking sheet for 2 minutes before transferring to a baking rack to cool.

Cool completely then top with frosting.

Frosting

In the bowl of a stand mixer fitted with the paddle attached, beat butter until fluffy.

Add additional sugar, 1/2 cup at a time, to reach desired consistency and sweetness.