Cook a thick porridge from milk, rice, salt and lemon peel and let cool down a little.
In the meantime, peel and quarter the apples and remove the core. Cut the pulp into small pieces. Drizzle with lemon juice and mix with the raisins to taste.
Mix the butter, sugar and egg yolks together until frothy. Gradually stir in the rice pudding well. Beat the egg whites into very stiff snow and fold in.
Now alternately fill the rice porridge with the apples in a baking dish. Start with rice and end with rice. Cover with flakes of butter and bake the casserole in a preheated oven at 180 degrees for 45 minutes. The top layer should be golden brown.
If you don`t like warm fruit, you can just leave it out, the casserole tastes delicious even without, but with compote.