Preheat oven to 190°C (375°F) and line baking trays with parchment paper.
In a bowl whisk together flour, cream of tartar, baking soda, and salt.
In another bowl beat butter and sugar until light and fluffy.
Add eggs and vanilla extract and mix until combined.
Gradually mix dry ingredients into wet ingredients until a soft dough forms.
In a small bowl combine sugar and cinnamon for coating.
Scoop large dough balls and roll in cinnamon-sugar mixture.
Place on prepared tray spacing well apart.
Bake for 10–12 minutes until edges are set and centers look slightly soft.
Cool on tray for 5 minutes before transferring to a wire rack.
