Pre-heat oven to 150°C/300°F and lightly spray your ramekins with cooking spray (see notes)
In a saucepan over high heat, stir the cream, milk, chocolate and vanilla until it just comes to a boil. Set aside
In a large mixing bowl, whisk the eggs, yolks and caster sugar until well combined.
While whisking, gradually add the hot milk mixture to the egg mixture and whisk until combined.
Pour the custard into the ramekins, then place ramekins into a baking dish.
Pour enough hot water into the baking dish, so the water comes halfway up the ramekins
Place baking dish in oven and bake for 40-45 minutes (see notes)
Remove from oven, then remove the ramekins from the water bath, resting them for 15 minutes before serving. Optional serving suggestion: serve chilled, topped with Chantilly Cream and chocolate shavings