Combine flour, baking powder, cinnamon and nutmeg.
Cream sugar and butter until light. Add eggnog, vanilla, and egg yolks; 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 1 inch apart. Sprinkle lightly with nutmeg. Bake 20 to 23 minutes until bottoms turn light brown.