Clean and wash the celery. Cut 250 g into fine slices, the rest into bite-sized pieces. Finely chop 4 plums. Fry celery slices, plums and rice in hot oil, add 300 ml water and bring to the boil.
Season with salt and pepper and let it swell at low heat for about 20 minutes. In the meantime wash the chicken and pat dry. Pour in rice mixture, close the opening with wooden skewers, tie up with kitchen string and place on the fat pan.
Pour hot clarified butter over it. Bake in the preheated oven (electric: 200 °C/ gas: level 3) for approx. 50 minutes. In the meantime peel, wash and cut carrots into small pieces. Cook remaining celery and carrots in boiling salted water for about 15 minutes and drain.
Halve the remaining plums. Deglaze the chicken with Armagnac and stock 5 minutes before the end of the cooking time. Remove chicken from the fat pan and keep warm. Pour the gravy through a sieve and toss the vegetables and plums in it.
Serve everything garnished with parsley and celery green.