Combine the ingredients in a small saucepan and let the sugar cook until it turns a deep amber color (watch carefully to prevent burning).

Immediately pour the caramel into 3–4 6oz ramekins, tilting to coat the bottoms (let it harden before adding the custard)

In a saucepan, heat the milk and vanilla until warm but not boiling.

In a bowl, whisk the egg yolks and sugar until light in color. Slowly add the warm milk, whisking constantly to prevent curdling.

Place the ramekins in a baking dish and strain the custard through a sieve into the caramel-lined ramekins.

Add hot water until it reaches halfway up the sides (bain-marie) and cover with aluminum foil.

Bake at 325°F/ 160°C for 35–40 minutes, or until the custard is set but slightly jiggly in the center.

Let cool, then refrigerate for at least 4 hours (or overnight).

To serve, run a knife around the edges and invert onto a plate to release the caramel sauce.