Lightly coat two 6 oz ramekins with nonstick cooking spray and set aside.

Place the chopped chocolate and unsalted butter in a medium microwave-safe bowl.

Microwave in 30 second intervals for 60 to 90 seconds, stirring after each interval, until fully melted and smooth, then let cool slightly.

In a separate bowl, whisk the eggs, egg white, and granulated sugar together until the mixture is pale and frothy.

Pour the egg mixture into the slightly cooled chocolate mixture and whisk until smooth and well combined.

Sprinkle the flour over the batter and gently fold with a spatula just until no dry streaks remain.

Divide the batter evenly between the prepared ramekins, filling each about three-quarters full.

Place the ramekins in the air fryer basket, leaving space between them, and cook at 375°F for 8 to 10 minutes, until the tops are puffed, edges look set, and centers are slightly soft.

Remove the ramekins from the air fryer and let them sit for 1 minute.

Run a thin sharp knife around the edges of each cake to loosen.

Invert a serving plate over each ramekin, carefully flip, lift off the ramekin, and dust the tops with confectioners sugar.

Serve immediately while the centers are still molten.