Heat the oil in a non-stick frying pan. Add the veal cubes and brown on all sides. Transfer with a slotted spoon to a casserole. Add the onion to the pan and fry until golden brown. Add to the casserole.

Stir the flour into the fat remaining in the pan and cook for 3 minutes. Gradually stir in the stock and orange juice and bring to the boil.

Season with salt and pepper to taste. Pour over the veal cubes. Arrange the orange slices, overlapping, on top.

Cook in the oven for 1 1/2 - 2 hours, or until the veal is tender. Garnish with watercress.

Depending on the time of year different varieties of oranges are available. The best types to use in casseroles are those with thin skins, juicy flesh and few pips, such as the Navel and Valencia.