Preheat the oven to 400 degrees and line a baking sheet with parchment paper. Set aside.
In a medium bowl, whisk together the flour, cream of tartar, baking soda, and salt.
In another medium bowl, beat the butter and both sugars until the mixture is creamy.
Now add in the egg and yolk and beat until fully incorporated.
Gradually add the dry ingredients into the wet ingredients, mixing until fully combined.
In a small bowl, mix together the sugar and cinnamon.
Using a teaspoon, drop a rounded 1” ball into the cinnamon sugar mixture to coat and then place on the prepared baking sheet.
Bake for 7 minutes, remove from the oven, and let the cookies sit on the baking sheet for 5 minutes before transferring to a wire cooling rack.