Preheat oven to 350.

Line a baking sheet with parchment paper and set aside.

Whisk together flour, baking powder, cinnamon, and nutmeg.

In nother bowl, cream butter and sugar together.

Add egg yolks, vanilla and eggnog and beat until smooth.

Gradually add dry ingredients into the wet ingredients and stir until combined.

Chill dough for at least 30 minutes.

Place teaspoon sized balls of dough onto the prepared sheet.

Bake for 18 minutes or until bottoms are lightly browned.

Place cookie on a wire rack to cool.

Mix together powdered sugar, butter and eggnog until blended.

Spread icing on cooled cookies and sprinkle with nutmeg.