Pre-heat the oven to 400ºF, or pre-heat your air fryer to 330ºF.

Butter and sugar two 6-ounce ramekins.

Melt the chocolate and butter together, either in the microwave or in a double boiler.

In a separate bowl, beat the egg yolks vigorously. Add the sugar and the vanilla extract and beat well again. Drizzle in the chocolate and butter, mixing well. Stir in the flour, combining until there are no lumps.

In a separate bowl, whisk the egg whites to soft peak stage. Fold the whipped egg whites into the chocolate mixture gently and in stages.

Transfer the batter carefully to the buttered ramekins, leaving about ½-inch at the top.

Place the ramekins on a baking sheet and transfer to the middle rack in the oven. Bake for 15 to 20 minutes. If using an air fryer, air-fry for 14 minutes at 330ºF.

Dust with powdered sugar and serve immediately with heavy cream.