Preheat the oven to 160°C. Heat the oil and butter in a large frying pan and, when sizzling, brown the meat on both sides and remove to a large casserole dish. You may need to do this in 2 batches so the meat doesn’t stew. Add the onion, celery and garlic to the same pan, adding a little more oil only if needed, and sauté until the vegetables are translucent. Stir in the flour mix and cook, stirring well, for a minute. Add the vermouth or wine, both types of tomatoes and the Simon Gault Home Cuisine beef stock, mix well, then pour over the meat. Place the lid on the casserole and cook in the oven for 1 1⁄2 hours, or until the meat is tender. (This can also be cooked on the stovetop if the casserole is flameproof.) To make gremolata, combine the parsley, lemon rind and garlic. Garnish the osso buco with gremolata and serve with risotto Milanese (link to the other recipe) and steamed broccoli, if desired.