Thoroughly mix the flour, cream of tartar, baking soda, cinnamon, and salt in a large bowl.

Add the room-temperature unsalted butter and sugar to another large bowl. Use an electric hand mixer or stand mixer to combine the butter and sugar. Then, add the eggs and vanilla extract. Combine everything with your mixer.

Once the wet ingredients are combined, add the dry ingredients to the bowl a little bit at a time. Continue to use your mixer on low to combine all of the ingredients. *If the batter is too dry, add a splash of milk.

Transfer the combined cookie dough to a bowl. Cover the bowl with plastic wrap and chill the dough in the refrigerator for at least 3 hours or overnight. The dough is wet and sticky so it will need time to chill and become firm.

Once the dough has chilled, remove the plastic wrap. Then, use a 1-tablespoon cookie scoop and roll the dough into balls with your hands. With the batter, make 28-32 cookies. Also, fill a bowl with 3 tablespoons of sugar and 1/8 teaspoon of cinnamon. Then, roll each ball of cookie dough in the sugar or monk fruit and cinnamon.

Place the cookie dough balls on a sheet pan with parchment paper. There is no need to press them down. Bake the cookies at 350°F for 7-9 minutes. Once they are cooked, let them slightly cool and enjoy!