Preheat oven to 350°F.

In a medium sized bowl, whisk together flour, baking powder, salt, nutmeg and cinnamon.

In the bowl of an electric stand mixer, whip together butter, granulated sugar and brown sugar until pale and fluffy.

Mix in egg yolks one at a time, blending just until combined after each addition.

Mix in vanilla extract, rum extract and egg nog.

Slowly add in dry ingredients and mix just until combined.

Use a tablespoon, scoop out dough, forming a ball. Place on silpat on a cookie sheet and slightly flatten.

Bake for 11 - 13 minutes.

Allow to rest on baking sheet several minutes before transferring to a wire rack to cool.

Cool completely before frosting.

Whip the butter in a stand mixer until pale and fluffy.

Add the extract, icing sugar, and 3 tablespoons of eggnog.

Whip until mixed, adding a tablespoon at time of eggnog until a spreadable consistency.

Sprinkle with freshly grated nutmeg and / or sprinkles.