01 -
Preheat oven to 350°F and line baking sheets with parchment paper or silicone mats.
02 -
In a medium bowl, whisk together flour, cream of tartar, 2 teaspoons ground nutmeg, baking soda, and salt.
03 -
In a large bowl, beat unsalted butter and 1 1/2 cups sugar together until smooth and creamy. Scrape down the bowl as needed.
04 -
Add egg, egg yolks, rum extract, and vanilla extract to the butter mixture. Mix until fully combined and smooth.
05 -
Gradually add the dry ingredients to the wet mixture, mixing just until a soft dough forms.
06 -
In a small bowl, whisk together 1/3 cup granulated sugar and 1/2 teaspoon ground nutmeg. Transfer to a shallow plate.
07 -
Scoop about 1.5 tablespoons of dough for each cookie and roll into balls. Coat each ball thoroughly in the sugar-nutmeg mixture.
08 -
Place coated dough balls about 2 inches apart on the prepared baking sheets. Bake for 12 minutes, until edges are set.
09 -
Allow cookies to cool on the baking sheets for at least 10 minutes before transferring to a wire rack.