Make the cinnamon sugar. In a small bowl, mix 1/2 cup granulated sugar with 2 tablespoons ground cinnamon. Set aside for rolling.

Whisk the dry ingredients. In a medium bowl, whisk together flour, cream of tartar, baking soda, and salt until evenly combined.

Cream the butter and sugar. In a large bowl, beat softened butter and 1 1/2 cups granulated sugar with a hand mixer until light and fluffy, about 2–3 minutes. Scrape the bowl as needed.

Add eggs and vanilla. Beat in eggs one at a time, then mix in the vanilla until smooth.

Bring it together. Add the dry ingredients to the wet in two additions. Mix just until a soft dough forms. Do not overmix.

Chill the dough. Cover and refrigerate for at least 30 minutes. Chilled dough spreads less and gives that classic crinkle.

Preheat the air fryer. Set to 320°F (160°C) for 3–5 minutes. Line the basket with a perforated parchment liner or lightly spray with nonstick spray.

Shape and coat. Scoop 1–1.5 tablespoon portions and roll into balls. Toss each ball in the cinnamon sugar to coat thoroughly.

Arrange in the basket. Place dough balls in a single layer, leaving about 2 inches between them. Avoid overcrowding; plan to bake in batches.

Air fry. Cook at 320°F (160°C) for 6–8 minutes. Cookies should look puffed with set edges and soft centers. They’ll firm up as they cool.

Rest and repeat. Let cookies cool in the basket for 2 minutes, then transfer to a rack. Repeat with remaining dough, keeping the dough chilled between batches.

Optional finish. While warm, you can lightly dust with extra cinnamon sugar for extra sparkle and crunch.