In a bowl with a hand mixer (or standing mixer), cream the butter with the sugar until light and fluffy.

Beat in eggs, one at a time.

In a separate bowl, mix flour, cream of tarter, baking soda, and salt.

Slowly add dry ingredients into wet ingredients. Once combined, chill the dough at least 1-2 hours.

Preheat the oven to 400.

Mix cinnamon and sugar together in a small bowl.

Roll the dough into 1 Tbsp sized balls. Then, roll in the cinnamon sugar mixture until the whole ball is coated.

Place on a greased cookie sheet and bake about 7-9 minutes, or until lightly browned but still soft. The key is to let them puff up and crinkle in the oven (getting lightly brown) and then taking them out before they flatten. They will flatten as they cool, giving them that perfectly chewy texture (if they flatten in the oven, they will be crunchy instead of chewy).

Enjoy!