Cook the rice with milk and sugar until soft. Separate the eggs and whip the egg whites with a pinch of salt until stiff peaks form. Add the egg yolks, butter, and cottage cheese to the warm rice. Season with vanilla and lemon zest. Finally, fold in half of the whipped egg whites. Transfer the rice mixture to a baking dish greased with butter. You can also add your favorite fresh or frozen fruit. Layer the remaining egg whites on top. Bake at 180°C for about 25 minutes.