Preheat the Oven: Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper.
Cream the Butter and Sugars: In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy. This should take about 2-3 minutes.
Add the Eggs and Vanilla: Beat in the eggs one at a time, making sure each is fully incorporated before adding the next. Mix in the vanilla extract.
Combine the Dry Ingredients: In a separate bowl, whisk together the flour, baking soda, cream of tartar, salt, and 2 teaspoons of the ground cinnamon.
Mix the Dough: Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix the dough.
Prepare the Cinnamon Sugar Coating: In a small bowl, combine the remaining 2 teaspoons of ground cinnamon with ½ cup of granulated sugar. Mix well.
Form the Cookies: Scoop out tablespoon-sized portions of dough and roll them into balls. Roll each ball in the cinnamon sugar mixture until fully coated.
Bake the Cookies: Place the coated dough balls onto the prepared baking sheet, leaving about 2 inches between each cookie. Gently press down on each ball to flatten slightly.
