Combine flour, baking powder, cinnamon and nutmeg. Cream sugar and butter until light. Add eggnog, vanilla, and egg yolks and beat at medium speed with mixer until smooth Add flour mixture and beat at low speed until just combined. Do not overmix.
Drop by teaspoonfuls onto ungreased cookie sheet one inch apart. Sprinkle lightly with nutmeg.
Bake 20 to 23 minutes until bottoms turn light brown.