Make the caramel. Place the sugar and measurement water in a saucepan and cook over a low heat until the sugar has dissolved. Increase the heat and cook until it is a caramel colour. Divide between 4 dariole moulds, coating the bases and a little up the sides.
Place the orange rind, 400 ml (14 fl oz) of the orange juice and the sugar in a saucepan and cook over a low heat until the sugar has dissolved. Mix the cornflour with 2 tablespoons of the remaining orange juice (or water), then stir into the pan and cook for 2 minutes until thickened. Pass through a fine sieve and leave to cool slightly.
Beat the eggs and egg yolks in a large bowl, then stir in the orange mixture, a little at a time. Spoon into the prepared moulds, place in a roasting tin and pour in boiling water to come two-thirds up the sides of the moulds. Bake in a preheated oven, 150°C (300°F), Gas Mark 2, for 20–25 minutes until just set with a slight wobble in the centres.
Leave to cool, then chill for at least 2 hours or overnight. Turn out on to serving plates and serve.