Sauté the onion, apple, celery and ham in butter for two minutes. Sprinkle with curry to taste. Add the rice and stir briefly. Pour the chicken stock on top. Let it simmer until the rice is ready.
Meanwhile, whisk together white wine, cream, egg yolk and starch. Add at the end of the cooking time and bring to the boil again briefly.
Vegetarians can omit the ham and use vegetable broth. White bread is also very tasty.