In a medium bowl, mix together the flour, cream of tartar, baking soda, cinnamon and nutmeg.
In the bowl of a stand mixer, cream together the butter and sugars until light and fluffy.
Add in the egg and mix until fully combined. Mix in the eggnog and vanilla.
Slowly mix the dry ingredients into the wet ingredients until fully combined.
Cover and refrigerate for at least 2 hours.
Preheat the oven to 375°F. Line a baking sheet with parchment paper and set aside.
In a small bowl, combine the cinnamon sugar ingredients.
Create cookie dough balls with a medium cookie scoop, and roll in the cinnamon sugar. Place on the prepared baking sheet at least 1.5 inches apart.
Bake in the preheated oven for 8-10 minutes, or until the edges are golden brown. Allow to cool on the baking sheet.