Preheat the oven to 120ºC.

Pick the parsley leaves from the stalks. Keep the leaves separate and finely cut the stalks. Scrub the lemon well under lukewarm running water and remove 2 strips of zest with a peeler. Grate the rest of the lemon zest on a fine grater and save this lemon zest.

Sprinkle the flour over a plate and mix in some salt and freshly ground pepper. Stir the veal shanks into the flour and shake off the excess. Heat the olive oil in a large frying pan and fry the shanks on both sides until light brown. Add the onion, celery and finely chopped parsley stalks and fry for a few minutes. Pour the white wine into the pan and let it sparkle. Add the tomato pieces, the stock, the lemon peel, the bay leaf and a pinch of salt and bring everything to the boil. Place a lid on the pan and slide it into the middle of the oven. Let the shanks stew for 2 hours.

Meanwhile, make the gremolata: peel the garlic clove and finely chop it. Finely chop a hand of the retained parsley leaves. Sweep the garlic and parsley together in a pile on the cutting board, also add the lemon zest and finely chop these three together.

Check the ossobuco. It is ready when the meat almost automatically releases itself from the bone. Allow to simmer a little further if necessary.

Sprinkle with the gremolata before serving.