Boil 1 litre of milk, add rice, 1 pinch of salt and lemon zest. Let it swell for about 30 minutes at low heat, stirring occasionally. Wash, halve and stone the plums.
Bring 1/8 litre water, 1 tablespoon sugar and cinnamon stick to the boil, add plums and simmer for about 5 minutes. Remove from the heat. Remove lemon peel. Separate eggs. Beat the egg whites until stiff, adding 3 tablespoons of sugar.
Fold in the almonds. Mix the egg yolks with 2 tablespoons of milk and stir into the rice pudding with 2 tablespoons of sugar. Halve the beaten egg white, fold half into the rice pudding. Grease casserole dish. Drain plums, remove cinnamon stick.
Drain the plums. Place the rice and plums in an ovenproof dish, finishing with a layer of plums. Spread the rest of the beaten egg white in tuffs on the plums, sprinkle with brown sugar.
Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for approx. 10 minutes.