Preheat the oven to 325ºF. Line two large baking sheets with parchment paper.

In a large bowl using a handheld mixer beat the butter on high speed for 1 minute until creamy. Add the powdered sugar, nutmeg, and rum extract and mix until combined. Add the cornstarch and flour and mix on low until incorporated. Turn up the mixer to high speed and whip for 2 full minutes or until fluffy.

Roll the cookie dough into balls using about 1 tablespoon of dough per cookie and arrange on the prepared baking sheet, leaving 1 inch of spreading room between each cookie. Bake the cookies one pan at a time for 22-25 minutes or until the bottoms are lightly golden brown.

Place the extra powdered sugar in a small bowl and roll each cookie in the icing sugar to coat as soon as they come out of the oven being careful not to burn yourself or break the cookies.

Let the cookies cool fully on a wire rack. Enjoy!