16 Tablespoons (2 sticks) of Unsalted Butter, at room temperature
1 1/2 Cups of White Granulated Sugar
2 Large Eggs, at room temperature
1/4 Cup of Granulated Sugar (for coating)
1 1/2 Tablespoons of Ground Cinnamon (for coating)
Whisk flour, cream of tartar, baking soda, and salt together and then set aside.
In a large bowl, using a handheld mixer (or stand mixer with paddle attachment) on medium, beat the butter, 1 1/2 cups sugar, and vanilla together until light and fluffy (3 to 4 minutes). Reduce speed to low. Add the eggs one at a time, beating well after each addition.
Scrape the sides and bottom of the bowl and then add the flour mixture in three parts, just mixing until it disappears. Wrap dough with plastic wrap and chill for at least 30 minutes or up to 3 days.
In a small bowl, mix 1/4 cup granulated sugar and cinnamon for the coating.
Preheat your over to 400 degrees F. Line baking sheets with parchment paper.
Shape heaping-tablespoon-sized mounds of cookie dough into balls. Roll in the cinnamon mixture and place 2 inches apart onto baking sheets.
Bake the cookies for 8 to 10 minutes, or until the cookies have puffed a little and the tops look set. The cookies should be light golden. Cool on baking sheet for 5 minutes then transfer to a cooling rack to cool completely (cookies will fall a bit as they cool).