Make the cinnamon sugar. In a shallow dish, mix the 1/2 cup sugar with 1–2 teaspoons cinnamon. Set aside for coating.

Prep the air fryer. Preheat to 375°F (190°C) for 5 minutes. Line the basket with a perforated parchment liner, if you have one, to help with sticking.

Cook the dough base. In a medium saucepan, combine water, butter, 2 tablespoons sugar, and 1/2 teaspoon salt. Bring to a gentle boil over medium heat, stirring to melt the butter.

Add the flour. Remove from heat, add the flour all at once, and stir vigorously with a wooden spoon until a smooth dough forms and pulls away from the sides. Return to low heat and cook, stirring, for 1–2 minutes to dry the dough slightly. You’ll see a thin film on the pan.

Cool slightly and add eggs. Transfer dough to a bowl. Let it cool 3–5 minutes so it doesn’t scramble the eggs. Beat in the vanilla, then add eggs one at a time, mixing well after each. The dough should be thick, glossy, and pipeable. If it looks greasy or loose, rest it 2 minutes and mix again.

Fill the piping bag. Spoon the warm dough into a piping bag fitted with a large star tip. Twist the top to seal.

Pipe the churros. Lightly spray the parchment or a silicone mat. Pipe 4–6 inch lengths, spirals, or sticks. Use scissors or a knife to snip ends. Space them so air can circulate.

Lightly oil the surface. Mist the tops with neutral oil spray. This helps browning and prevents dry spots.

Air fry in batches. Arrange churros in a single layer in the preheated basket. Cook at 375°F (190°C) for 8–10 minutes, turning once halfway, until golden brown and crisp. Thicker churros may need up to 12 minutes. Avoid overcrowding.

Toss in cinnamon sugar. While warm, transfer churros to the cinnamon sugar and roll to coat. Work in small batches so the sugar sticks.

Make the chocolate sauce. Heat the cream in a small saucepan until steaming but not boiling. Remove from heat, add the chopped chocolate, and let sit 1 minute. Whisk until smooth, then whisk in butter, vanilla, and a pinch of salt. If needed, warm gently to loosen.

Serve. Plate the churros with a bowl of warm chocolate sauce. Serve immediately for best crunch.