Heat up a pan with the butter over medium heat, stir and cook for 1 minute.
In a bowl, mix egg with vanilla extract and sugar and stir well.
Add melted butter, flour and half of the chocolate chips and stir everything.
Transfer this to a pan that fits your Yedi Houseware air fryer, spread the rest of the chocolate chips on top, introduce in the fryer at 330 degrees F and cook for 25 minutes.