Preheat your oven to 425°F (220°C).

Grease four ramekins with butter and dust with flour.

In a heatproof bowl, combine the butter and chocolate chips. Melt together in the microwave or over a double boiler until smooth, stirring frequently.

In another bowl, whisk together the eggs, egg yolks, and sugar until frothy.

Pour the melted chocolate mixture into the egg mixture, stirring gently.

Gently fold in the flour and salt until just combined.

Divide the batter evenly among the prepared ramekins, filling them about ¾ full.

Bake in the preheated oven for 12 minutes.