Butter two 6 ounce ramekins and dust with granulated sugar.

In a medium saucepan, heat the butter, chocolate and cream over medium-low heat, stirring often, until the chocolate is melted and smooth.

Remove from heat and stir in vanilla. Whisk in flour until mixture is smooth.

In a small bowl, whisk sugar, egg and egg yolk until thick and pale. Fold egg mixture, 1/3 at a time, into chocolate mixture until well combined.

Divide the batter between the prepared ramekins. Preheat air fryer to 300 degrees.

Cook for 8-10 minutes, or until edges are firm but centers are just set. Transfer to a wire rack and cool for 5 minutes. Top with whipped cream, ice cream or fresh berries, if desired.