Preheat the
oven to moderate 160C (315F/Gas 2-3). Grease a 1.75 liter ovenproof dish
with butter. Half fill a baking dish with water and place in the oven.
Wash the rice and leave it to drain in a sieve for 10 minutes. Bring 2/3
cup (170ml / 5.5 fl oz) water to the boil in a heavy-based pan, stir in
the rice and boil for 2 minutes, or until the water is absorbed. (Watch
the rice does not stick to the pan.) Stir in the milk and lemon rind,
and bring to the boil, stirring. Reduce the heat and simmer for 15
minutes, or until the rice is cooked, stirring occasionally. Cool for 5
minutes, then whisk in the cream, egg yolks and sugar, to taste.
Beat the egg
whites in a small bowl until soft peaks form. Gently fold into the rice
mixture and pour into the dish. Place the dish in the baking dish and
bake for 60 minutes, or until just lightly browned on top. Cover with
foil and bake for 20 minutes, or until set. Sprinkle with sifted icing
sugar and serve warm with whipped cream.