Preheat and prep: Preheat your air fryer to 375°F (190°C) for 3–5 minutes. Lightly spray the basket with oil to prevent sticking.

Make the dough (choux): In a medium saucepan, combine water, sugar, salt, and butter. Bring to a gentle boil over medium heat. Add the flour all at once and stir constantly with a wooden spoon until the dough forms a ball and pulls away from the pan, about 1–2 minutes.

Cool slightly and add egg: Transfer the dough to a bowl. Let it cool for 3–4 minutes so it doesn’t scramble the egg. Add the egg and vanilla, then beat vigorously until smooth and glossy. The dough should be thick but pipeable.

Set up the coating: In a shallow bowl, mix granulated sugar, cinnamon, and a pinch of salt. Set aside. Melt the 2 tablespoons of butter if you prefer a richer coating later.

Form the bites: Transfer the dough to a piping bag fitted with a large star tip, or use a zip-top bag with a corner snipped off. Pipe 1-inch to 1 1/2-inch pieces onto a parchment-lined tray, then use scissors or a knife to cut them cleanly. If you don’t want to pipe, drop small spoonfuls and lightly shape them with damp fingers.

Lightly oil and air fry: Mist the dough pieces lightly with oil spray. Arrange them in a single layer in the air fryer basket, leaving a little space between each. Air fry for 7–9 minutes, flipping halfway, until golden brown and crisp on the edges. Work in batches as needed.

Coat immediately: While hot, either brush or toss the bites with melted butter (optional), then roll in the cinnamon sugar until well coated. If you skip the butter, press the sugar mixture on gently so it adheres.

Serve warm: Pile the churro bites onto a plate and serve with chocolate sauce, dulce de leche, or your favorite dip. Enjoy right away for the best texture.