Peel and wash the potatoes and celery and cut into small pieces. Cook in boiling salted water for about 20 minutes. In the meantime, wash the steaks and pat them dry. Peel shallots. Wash parsley and chop finely.
Mix lemon zest and parsley. Heat the oil. Fry the shallots in it for 2-3 minutes, push aside. Fry the steaks in cooking fat for 3-5 minutes on each side, season with salt and pepper and remove.
Stir the stock and jam into the roast mixture, boil down over high heat for about 2 minutes, season with salt and pepper. Drain the vegetables and let them steam. Add butter and cream, mash finely, season to taste with salt, pepper and nutmeg.
Serve puree, steaks and shallots with some sauce and parsley mixture in portions, garnished with lamb's lettuce and carambole.