Mix in the butter and flour.
Add the milk and cooking juices of meat, then season.
Add a little butter, cheese, ham and mushrooms(browned already in butter).
Put some sauce in between each slice of meat and tie together.
Put some of the sauce on top, sprinkle with leftover cheese and allow to brown in the oven.
NB:The veal should be without bone, cooked in advance and stuffed with mushrooms and cheese and kept in the fridge.If meat is cold, heat for approx. 20 min to half an hour.