Preheat oven to 350F and line a large baking sheet with parchment paper.
In a medium-sized bowl, whisk together the almond flour, cornstarch, cinnamon, baking soda, cream of tartar and salt.
In a large mixing bowl, use an electric mixer to cream together the butter and sugars, stopping to scrape down the sides of the bowl as necessary. This will take about 2-3 minutes.
Add the egg and vanilla and beat until combined.
On low speed, gradually mix in the dry ingredients until just combined.
In a small bowl, combine the 2 tablespoons of granulated sugar and 1/2 teaspoon cinnamon for the coating.
Use a 1.5 tablespoon cookie scoop to portion out the cookie dough and roll into balls. Roll in the cinnamon sugar mixture.
Arrange the cookie dough balls on the prepared baking sheet, about 2-3 inches apart. (I usually bake 6 per pan). Bake 9-11 minutes or until the cookies are puffy and still look a little underdone.
Let cool on the pan for 10 minutes before transferring to a wire rack to cool completely.
Repeat with remaining dough.
Notes
If the dough feels too soft or sticky, you can refrigerate it for 30 minutes before rolling into balls.
To ensure the cookies stay soft and puffy, it's better to underbake these cookies than over bake them.
Ovens can vary in terms of temperature so start checking on the cookies at around 9 minutes.
Let the cookies cool on the pan for at least 10 minutes. They will firm up as they cool.
If you don't have a kitchen scale to weigh your ingredients, make sure you use the spoon and level method for your flour. (This will ensure you don't use too much flour).