In a medium saucepan, mix together 1 cup of water, 75g of unsalted butter, a pinch of salt, and 25g of sugar. Bring this mixture to a rolling boil over medium heat, ensuring the butter fully melts. Once boiling, remove the pan from heat and immediately stir in 1 cup of plain flour, mixing vigorously until a smooth dough forms that pulls away from the sides of the pan.

Transfer the dough into a mixing bowl and allow it to cool for about 4-5 minutes. Once slightly warm, add 1 large egg and 1 teaspoon of vanilla essence to the bowl. Beat the mixture until fully combined and smooth.

Preheat the air fryer to 375°F (190°C) for about 3-4 minutes. Lightly spray the basket with non-stick cooking spray.

Fit a piping bag with a large star tip and fill it with the churro dough. Pipe bite-sized churro shapes directly into the air fryer basket. Brush the tops lightly with melted butter, then air fry for 10-12 minutes.

While the churro bites are still hot, prepare the cinnamon-sugar coating by mixing 200g of sugar with 8g of cinnamon in a shallow bowl. Toss the churro bites in the mixture, ensuring each piece is generously coated.