• Preheat the oven to 350°F and line a couple baking sheets with parchment paper.
• In a mixing bowl, whisk together the flour, cream of tartar, salt, baking soda, cinnamon, and nutmeg. Set aside.
  2 ¾ cups all purpose flour, 2 tsp. cream of tartar, 1 tsp. salt, 1 tsp. baking soda, ¾ tsp. ground cinnamon, ¾ tsp. ground nutmeg
  
• In a stand mixer fitted with the paddle attachment, beat together the shortening and sugars on medium high speed until light and fluffy, about 2-3 minutes, scraping down the sides of the bowl as needed.
  1 cup vegetable shortening (such as Crisco), 1 cup granulated white sugar, ¼ cup dark brown sugar
  
• Add the egg, egg yolk, eggnog and extracts and mix again until combined, once again scraping down the sides of the bowl with a rubber spatula as needed.
  1 large egg, 1 large egg yolk, 2 Tbsp. eggnog, full fat, 1 tsp. rum extract, 1 tsp. vanilla extract
  
• Gradually add in the dry ingredients just until incorporated.
  
• The dough may be a little sticky, but shouldn’t be terrible to work with. Feel free to chill the cookie dough for a bit, if needed.
• In a small dish, combine the sugar, cinnamon and nutmeg.
  2 Tbsp. granulated white sugar, ¾ tsp. ground cinnamon, 1 pinch ground nutmeg
  
• Scoop the cookie dough into about 1 ½ - 2 tbsp. sized balls, roll, and coat in cinnamon sugar mixture.
  
• Place on prepared baking sheet and bake for just 8-10 minutes, careful not to overbake.
• They look very soft and puffy right out of oven and almost underbaked, but as they cool, they’re perfectly soft and chewy. Let cool on the cookie sheet for just 1 minute, then carefully transfer to wire rack to cool completely. They settle as they cool.
  

Make the eggnog cream cheese frosting

• Using a hand held mixer or a stand mixer fitted with the paddle attachment, beat the softened cream cheese and butter on medium speed until it's creamy (about 2 minutes).
  8 oz. cream cheese, full-fat, 4 Tbsp. unsalted butter
  
• Add in the eggnog, rum extract and a pinch of cinnamon nutmeg, and salt.
  2 Tbsp. eggnog, full fat, 1/2 tsp. rum extract, 1 pinch ground cinnamon, 1 pinch ground nutmeg, 1 pinch salt
  
• Then add in the powdered sugar. Beat on low just to get it combined the increase to medium-high speed until fully incorporated. Adjust as needed, adding more powdered sugar is the buttercream is too thin or a touch more eggnog if too thick.
  3-4 cups powdered sugar
  
• Pipe on frosting using a piping bag fitted with a small round tip. Garnish with freshly grated nutmeg, yum!!