Preheat oven to 350°F and line baking sheets with parchment paper or silicone baking mats.
In a stand mixer or large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add eggs and vanilla extract. Mix until fully combined.
In a separate bowl, whisk together flour, baking soda, salt, and cream of tartar.
Slowly add the dry ingredients into the wet ingredients, mixing just until combined. Do not overmix.
In a small bowl, mix together the cinnamon and sugar coating.
Scoop dough into balls and roll each one in the cinnamon sugar mixture until fully coated.
Place dough balls onto prepared baking sheets, leaving space between each cookie.
Bake for 9–11 minutes, until the edges are set but the centers still look slightly soft.
Let cookies cool on the baking sheet for a few minutes before transferring to a cooling rack.
Optional: While still warm, roll the tops lightly in extra cinnamon sugar for an extra cozy finish.