In a large mixing bowl, whisk together flour, baking powder, soda, cream of tartar and salt. Set aside.
1 ½ cup all-purpose flour, ½ teaspoon baking powder, ¼ teaspoon baking soda, ½ teaspoon cream of tartar, ¼ teaspoon salt
Place butter in a glass microwave-safe bowl. Microwave for 20 seconds, check and microwave for 10 more seconds if needed. See note for tips!
½ cup unsalted butter
Cool butter completely. Add both sugars and whisk for 20 to 30 seconds. Add egg and vanilla and whisk just until combined.
½ cup granulated sugar, ¼ cup brown sugar, 1 large egg, 1 teaspoon pure vanilla extract
Add dry ingredients to wet ingredients and stir with a wooden spoon until all ingredients are combined.
Cover the bowl with dough and chill for at least 30 minutes.
Line a baking sheet with parchment paper or silicone baking mat.
Preheat oven to 350° F.
In a small mixing bowl or ramekin, combine granulated sugar and cinnamon. Scoop the cookie dough with a 1 ½-tablespoon size cookie scoop, roll into a ball and roll in cinnamon sugar. Place on prepared baking sheet, spacing the dough balls at least 2 inches apart.
⅓ cup granulated sugar, 1 ½ teaspoon ground cinnamon
Bake cookies for 9 to 11 minutes. For me the magic number was 10 minutes exactly. The cookies will look puffed up but will deflate while cooling and will have the classic snickerdoodle folds.
Notes
How to properly measure out flour: do not dip the measuring cup in flour bag. Stir the flour in the bag a few times, so it's not packed. Scoop the flour with a spoon into the measuring cup, then level off the top with a knife. Place flour in mixing bowl and repeat if needed.
Please note, that the nutrition value can vary depending on what product you use. The information below is an estimate. Always use calorie counter you are familiar with.