Stud the onion with the cloves.  Place the veal in a casserole dish and add the carrots, onion, leek and bouquet garni.  Pour in the wine and add just enough water to cover the meat and vegetables.  Bring to the boil, skimming the surface for the first 10 minutes of any scum.  Cover and simmer gently for 2.5 hours.

About 45 minutes before the end of cooking, prepare the garnish. Wash mushrooms, pat dry and cut into halves or quarters, depending on their size. Fry them at first without any oil or butter (my tip – not in the original recipe!) in a non-stick pan until they have given out all of their juices. This concentrates their flavour. THEN add 25g of the butter and the lemon juice to them and set aside. Sauté the onions in a small pan with the rest of the butter until golden.

Lift the lid of the casserole dish and smell these flavours! Discard the bay leaf and thyme stalks. Remove the meat and vegetables with a slotted spoon and transfer to a large serving dish, adding the mushrooms and pickling onions. Set aside and keep warm in a cool-moderate oven.

Boil the cooking liquid over a high heat until reduced. Meanwhile, in a bowl, hand-whisk the crème fraîche, lemon zest, yolks, grated nutmeg, and season with salt and pepper. Blend in 3 tablespoons of the hot stock then quickly whisk in the yolk mixture back into the stock. Stir constantly until thickened but do not boil (it will reduce its subtle flavours). Whisk until the sauce is smooth and velvety.