Following the manufacturer’s instructions, preheat the air fryer to 325 degrees F, air fryer setting.
Prepare a baking pan by spraying thoroughly with vegetable-based cooking spray.
Add butter, sugar, and water to a large saucepan and simmer over low heat for one minute.
Stir in 1 cup of chocolate chips until they have melted.
Remove from heat, stir in eggs and vanilla extract, combining thoroughly. Set aside.
Combine flour, baking powder, and salt in a separate bowl. Add chocolate mixture and stir well.
Fold in the remaining ½ cup of chocolate chips.
Place the brownie pan into the air fryer basket or on the air fryer tray. Cook for 20 – 25 minutes in the preheated air fryer (on the “air crisp or air fryer setting, depending on make /model of air fryer).
Cool for 15 minutes in the pan before cutting and serving.
Top with optional chocolate syrup, nuts, or other toppings.
Plate, serve, and enjoy!