Pat the Osso Bucco dry with paper towels. Generously season with sea salt and pepper.
In a heavy cast iron pan or dutch oven, sear the meat in the canola oil until it reaches a nice brown color. Remove from the pan and set aside.
Sweat the onions, celery, carrots, garlic and leeks in the meat drippings until so, about 10 minutes on medium low heat. Add the thyme, rosemary, wine and veal stock to the vegetable mixture and stir.
Place the Osso Bucco back into the pan with the braising liquid and cover. Transfer the pan into a preheated oven set at 325 degrees and roast for 3 ½ hours.