Grease 2 ramekins with cooking spray and then sprinkle each with a pinch of sugar.
In a microwave-safe bowl, add the butter, and chocolate and microwave on high heat for about 2 minutes or until melted completely, stirring after every 30 seconds.
Remove from microwave and stir the mixture until smooth.
In another bowl, add the egg yolks and beat well.
Add the sugar, and vanilla extract and beat well.
Add the chocolate mixture and mix until well combined.
Add the flour and mix well.
In a clean glass bowl, add the egg whites and beat until soft peaks form.
Fold the whipped egg whites in 3 portions into the chocolate mixture.
Place mixture into the prepared ramekins evenly and with the back of a spoon, smooth the top surface.
Slide the Air Fryer Basket inside and adjust the temperature of Air Fryer to 330 °F to preheat for 5 minutes.
After preheating, arrange the ramekins into the Air Fryer Basket in a single layer.
Slide the basket into Air Fryer and set the time for 14 minutes.
After cooking time is finished, remove the ramekins from Air Fryer and set aside to cool slightly.
Sprinkle with the powdered sugar and serve warm.