Take the shanks out of the refrigerator about 30 minutes before cooking.
Season the meat well on both sides with freshly ground black pepper and sea salt. Using a fine sieve, dredge the shanks with flour on both sides.
In a large ovenproof skillet over medium-high heat, add oil and clarified butter. When hot, working in batches, add the veal shanks and brown on all sides; transfer to a plate.
Reduce the heat to medium and add 2 tbsp. clarified butter.
Add onions and sauté until soft, about 5 minutes. Three minutes later, add ¼ cup white wine, stir and cook for another 2 minutes. Transfer the onions to a bowl; set aside.
Add carrots and celery to the skillet and cook for 8 to 10 minutes or until soft.
Preheat oven to 350ºF.
Add garlic and sauté for 1 minute. Pour in the remaining white wine and also Marsala. Scrape the bottom of the pan to dislodge any brown bits; cook for 2 minutes.
Add veal stock, chicken broth, diced tomatoes, thyme, rosemary and bay leaves. Gently stir the ingredients before returning the onions back to the skillet; stir again.
Carefully place the veal shanks back in the pan with their juices and press down gently to submerge the meat. Bring to a simmer, cover and transfer to the preheated oven. Cook for 1 ½ hours or until the meat is fork tender and falls off the bone.
Remove from the heat, spoon Orzo alla Milanese or regular risotto into each bowl, place an ossobuco on top, ladle in braising juices and vegetables over meat and then finalize by sprinkling on parsley and lemon zest.