Preheat oven to 150ºC (300ºF). Place the cream, milk, vanilla and chocolate in a saucepan over high heat and stir to melt the chocolate. Cook until the mixture just comes to the boil. Remove from heat and set aside.
Place the eggs, extra yolks and sugar in a bowl and whisk until well combined. Gradually add the hot cream mixture to the egg mixture, whisking well to combine. Strain into 6 x 1 cup-capacity (250ml) teacups. Place teacups into a water bath (see recipe notes, below). Bake for 45 minutes or until just set. Remove from the water bath and allow to stand for 15 minutes before serving. Serves 6.
TIP: This recipe is also delicious served chilled. Simply refrigerate until cold before serving.
recipe notes To make a water bath, place the custard dish into a deep-sided baking dish and pour in enough boiling water to come halfway up the sides of the custard dish. This will ensure an evenly cooked custard.