In a microwave-safe bowl, melt the chocolate and unsalted butter together in microwave, stirring every 20 seconds until fully melted. Set aside.
Whip the egg, egg yolk, vanilla extract, and sugar, in a bowl until frothy. Add in the all-purpose flour and temper in the chocolate mixture with the egg mixture.
Prepare the ramekins by spraying with cooking spray or rubbing with butter. Pour the mixture evenly between the ramekins.
Preheat your air fryer to 370F. Add the ramekins (might have to be in batches) and bake until the cake is set on the sides and runny in the middle, about 6-10 minutes depending on your air fryer.
Remove with oven mitts and let sit 1 minute. Run a butter knife around the outside of the cake and invert it on a plate. Top with confectioners sugar, whipped cream, or vanilla ice cream.