Beat the egg, vanilla and rum extract with the butter and sugar.
With the mixer on low, slowly add the dry ingredients The cookie dough will be wet.
Use a heaping tablespoon to drop the dough a few inches apart on a parchment lined baking sheet. Bake for 10 to 12 minutes.
Make the frosting then frost the cooled cookies. I like to make a swirl on the top. Sprinkle with ground nutmeg.