Preheat your oven to 425°F (220°C).

Grease four 6-ounce ramekins with unsalted butter and dust with flour.

In a microwave-safe bowl, combine the butter and chocolate chips. Microwave in 30-second intervals, stirring in between, until melted and smooth.

In a separate bowl, whisk together the eggs, egg yolks, sugar, and vanilla extract until well combined.

Gradually pour the melted chocolate mixture into the egg mixture, whisking continuously until smooth.

Gently fold in the flour and a pinch of salt until just combined.

Divide the batter evenly among the prepared ramekins, filling each about 3/4 full.

Place the ramekins on a baking sheet and bake for 12-14 minutes, until the edges are firm but the center is soft.

Let the cakes cool for 1 minute, then run a knife around the edges and invert onto serving plates.

Dust with powdered sugar and serve immediately, optionally with a scoop of vanilla ice cream.