In a saucepan over high heat, combine 1 cup of water, 1/3 cup plus 1 tablespoon of unsalted butter, 1 tablespoon of sugar, and 1 teaspoon of salt. Bring this mixture to a rolling boil, stirring occasionally. Once it reaches a boil, reduce the heat to low and gradually add 1 cup of plain flour, mixing until it forms a smooth dough.

Remove the saucepan from heat and allow the dough to cool for about 4-5 minutes. Once cooled, add 1 large beaten egg and 1 teaspoon of vanilla essence. Using an electric hand mixer, blend until the mixture is smooth and fully combined.

Preheat your air fryer to 375°F (190°C). Lightly spray the air fryer basket with non-stick cooking spray to prevent sticking.

Transfer the prepared dough into a piping bag fitted with a large star tip. Pipe bite-sized churro shapes into the air fryer basket, ensuring not to overcrowd them.

Lightly brush the churros with melted butter to enhance flavor and help the cinnamon sugar adhere. Place the basket in the preheated air fryer and cook for 10-12 minutes, or until golden brown.

While the churro bites are cooking, mix together 1 cup of white sugar and 1 tablespoon of cinnamon in a shallow bowl.

Once the churros are done frying, carefully remove them from the basket and toss them in the cinnamon-sugar mixture until fully coated.

Serve the churro bites immediately to enjoy their warm, soft center and crisp exterior.