Slowly cook the round grain rice in the salted milk until soft. Meanwhile, peel the apples (quantity depends on size and personal taste), remove the core and cut into small pieces.
Preheat oven to 180°C.
Separate the eggs and beat the egg yolks with butter, sugar and cocoa powder until foamy. Add the slightly cooled rice mixture and finally fold in the stiffly beaten egg whites.
Pour half of the mixture into a greased casserole dish, then add the apple pieces and the rest of the rice mixture. Bake at 180°C for about 40-45 minutes, sprinkle with sweetened cocoa powder and serve.