Preheat oven to 350f and set rack to the middle level. Line baking sheets with parchment paper or silicon baking mats.
In a medium bowl, combine the flour, cream of tartar, cinnamon, baking soda, and salt and set aside.
In a large bowl with a hand mixer, or the bowl of a stand mixer, cream the butter and sugar. Add the eggs and vanilla and mix until combined.
Combine the dry ingredients with the butter mixture and mix until combined.
In a small bowl, combine the ingredients for the cinnamon sugar coating.
Using a medium cookie scoop, scoop the dough out and roll it into a ball. Place the ball into the cinnamon sugar mixture and coat well. Place the dough ball onto the cookie sheet. Repeat for the remaining dough, spacing the balls ~3 inches apart.
Bake for 9-10 minutes or until the edges turn lightly golden. While the cookies are warm, lightly press the center down with a spoon to slightly flatten the cookies and if desired sprinkle extra cinnamon sugar on top. After 10 minutes of cooling, place the cookies onto a wire rack to completely cool before storing.