Add milk, cream, sugar and vanilla to a saucepan. Heat on medium and stir until the sugar has dissolved. Let the mixture summer until foamy on top like a latte.
1/4 cup caster sugar, 1 cup full cream milk, 1 cup thickened cream, 1 vanilla bean
In another bowl beat the eggs and egg yolk.
3 large eggs, 1 large egg yolk
Strain the milk mixture into another bowl or saucepan. Slowly pour the milk mixture into the eggs while whisking. This will temper the eggs. Pour into the cake tin.
Prepare a water bath by laying a towel in the bottom of a large baking dish. Place the cake tin in the dish and fill 2/3 way up with hot (not boiling) water. Cover the custard with foil, making two holes for steam to escape. Bake for about 55-60 minutes. The water should never boil.
Remove from the oven and water. Cool on the stovetop before refrigerating.
To serve, run the bald of a knife around the edge of the caramel, invert and serve very cold.