Generously butter the insides of the ramekins (bottom and sides), then dust with cocoa powder. Tap out the excess.
butter, unsweetened cocoa powder
Break the chocolate into pieces and cut the butter into cubes. Melt them together in a double boiler or in the microwave (in 20-second bursts), then stir until smooth and let cool slightly.
120 g dark chocolate, 80 g butter
Whisk the whole eggs, egg yolks, and sugar until the mixture is pale.
2 whole eggs, 2 egg yolks, 60 g granulated sugar
Pour the lukewarm melted chocolate into the egg mixture, then whisk until smooth.
Add the sifted flour and salt, then mix just until combined without overworking the batter.
40 g all-purpose flour, 1 pinch salt
Divide the batter among the ramekins, filling each about three-quarters full.
Air Fryer Cooking
Preheat the air fryer to 180°C.
Place the ramekins in the basket, spaced apart, making sure they do not touch each other or the heating element.
Cook for 8 to 9 minutes at 180°C without opening the basket. The edges should be set and the center should still wobble.
To Finish
Let the cakes rest for 2 minutes. Run a knife around the inside edge of each ramekin, then invert onto plates and unmold.
Dust with powdered sugar and serve right away.
powdered sugar
Notes
Baking tips: The timing window is narrow: at 180 °C in 7 to 8 cm ramekins, 8 min gives a very runny center, 8 to 9 min gives the perfect balance, and 10 min yields a tender cake without a molten center. Do not open the basket (each opening drops the temperature). Look for visual cues: the edges should be matte and set, the center should still wobble, and the surface should be lightly cracked and glossy; a toothpick should come out moist.Unmolding: Grease generously with butter, then dust with cocoa rather than flour. Wait exactly 2 minutes before unmolding: too early and it will collapse, too late and the center will set.Variations & make-ahead: The batter can be refrigerated for up to 24 h (already portioned into the ramekins and covered); let it sit out for 10 min before baking and add 1 to 2 min if it's still cold. Frozen ramekins can be cooked straight from frozen (+2 min). For a deeper cocoa flavor, add 1 tsp instant coffee to the batter.