Prepare the custard
Preheat the oven to 150°C / 130°C fan / gas 2. Lightly beat the eggs and extra yolk in a bowl with the vanilla and caster sugar until combined.
Pour in the milk and double cream, then stir gently until smooth.
Fill the dish
Pour the custard mixture into a medium ovenproof dish. Grate a generous layer of fresh nutmeg over the top.
Bake in a water bath
Place the dish inside a roasting tin. Pour hot water into the tin until it comes about three-quarters of the way up the sides of the custard dish.
Bake for 45–50 minutes, or until the custard is just set but still has a slight wobble in the centre.
Serve
Serve warm for a soft, comforting pudding, or leave to cool and chill in the fridge overnight. Lovely with poached fruit.