In a saucepan over medium heat, combine the water, butter, granulated sugar, and salt. Bring to a boil, stirring until the butter melts.
Remove the saucepan from heat and stir in the flour and baking powder until a dough forms. Let it cool for about 5 minutes.
Add the eggs one at a time, mixing until fully incorporated and the dough is smooth. Stir in the vanilla extract.
Preheat your Air Fryer to 375°F (190°C).
Transfer the churro dough to a piping bag fitted with a star nozzle. If you don’t have a piping bag, a ziptop bag with the corner cut off works as well.
Pipe 1-inch long pieces of dough directly into the Air Fryer basket, making sure they are spaced apart and not touching. You may need to cook them in batches.
Air fry the churro bites for 8-10 minutes, or until golden brown and crispy.
In a small bowl, combine the 1/4 cup granulated sugar and cinnamon.
Once the churro bites are cooked, remove them from the Air Fryer and immediately toss in the cinnamon sugar mixture until evenly coated.
Serve warm, and enjoy the deliciousness of your air-fried churro bites!