Set out all of the ingredients to come to room temperature.
Line your baking sheets with parchment paper and preheat the oven to 350F.
Cream the butter and sugar together with either a stand mixer or hand mixer on medium speed for about 3 minutes, or until the mixture is light and fluffy.
Add the eggs one at a time and mix them in until they are completely combined, then mix in the vanilla extract.
In a separate bowl, combine together the flour, cream of tartar, baking soda, and salt. Add it to the wet ingredients and mix until they have come together into a soft dough.
Mix the cinnamon and sugar in a bowl and set aside.
Portion the dough out into 1 ½-2 tbsp. portions and roll them in the cinnamon sugar mixture.
Place them about 2-3 inches apart on the cookie sheets, then place them on a rack in the center of the oven.
Bake for 8-10 minutes, then remove them from the baking sheets to a wire rack to cool. You can also adjust the baking time to add a minute or two if you prefer crunchier cookies.
Cool them completely before storing in an airtight container. They will keep for 4-5 days.