Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a bowl whisk together flour, baking soda, salt, and cream of tartar.
In another bowl beat butter and sugar until light and fluffy.
Add eggs one at a time and mix in vanilla extract until smooth.
Gradually mix dry ingredients into the wet ingredients to form a soft dough.
In a small bowl combine sugar and cinnamon for the coating.
Scoop dough, roll into balls, and coat each ball in cinnamon sugar.
Place dough balls on the baking sheet leaving space between each cookie.
Bake for 10–12 minutes until edges are set and centers stay soft.
Let cookies cool for a few minutes before serving.