Line a baking sheet with parchment paper. Bring the butter and eggs to room temperature (slightly warm).
In the bowl of your stand mixer with the paddle attachment, mix the softened butter, granulated sugar and light brown sugar on medium speed until light and fluffy, 1-2 minutes. See above for pictures. You can also use a hand mixer, you'll just have to mix for longer.
Add in the egg and egg yolk and mix on medium speed for 2-3 minutes until light and creamy. This gives lift to the cookies and will cause them to rise and fall, creating those beautiful cracks.
Add in the baking soda, cream of tartar, salt, cinnamon, and vanilla extract. Mix for 1 minute on medium, scraping the sides of the bowl.
Add the flour and mix on low until just combined.
Combine your cinnamon and sugar in a medium bowl, stir evenly to combine.
Use a medium cookie scoop to make 2-Tablespoon sized dough balls. Roll each into a ball shape and roll in cinnamon sugar mixture. I only coat the top in cinnamon sugar, but you can roll the entire ball if desired.
Place the cookie balls onto the prepared baking sheet about 2-3 inches apart.
Preheat oven to 350ºF (177ºC) and let your cookies rest at room temperature for 20 minutes while the oven heats up. This prevents over-spreading but it's optional.
Bake for 10-12 minutes, 10 if you want soft cookies, 12 if you want the edges to be slightly crispy.
Cool the cookies on the baking sheet for 5 minutes and transfer to a wire rack to cool completely. Store at room temperature for about 4 days.