Preheat the air fryer to 325℉ while you prepare the batter, about 5 minutes. Line the bottom and two sides of the baking dish with parchment, and spritz with non-stick spray. Use whatever pan you can find that fits your air fryer basket. 5”x7” or a 6” round pan are good sizes. 

In a medium microwave-safe bowl, heat the butter and chopped chocolate until the butter melts and the chocolate becomes soft, about 30 seconds. Whisk until the butter and chocolate are smooth. Add sugar, egg, and vanilla. Whisk to combine.

Sift in the flour, cocoa powder, baking powder, and salt and lightly mix with a spatula or large fork. Fold in the chocolate chips and place batter in the prepared pan. Smooth over the top with a spatula. The batter will be thick. Sprinkle with more chocolate chips if desired. 

Bake in the air fryer for 12-18 minutes or until a toothpick inserted in the center comes out mostly clean. Begin checking at 12 minutes, each air fryer cooks differently, and different pan sizes will affect cooking times. Let brownies cool for at least 15 minutes before cutting them.