Marco Canora has long been a chef's chef, turning out seemingly simple dishes that require years of training to prepare consistently and well. He's received wide-ranging accolades for his restaurants, including Hearth in New York City's East Village. Yet today Canora is achieving new fame for a food that takes almost no skill to make, uses no fancy ingredients, and is completely unglamorous: bone broth. Bone broth is exactly what it sounds like: a pile of animal bones, covered in water; some vegetable scraps; and often a bit of cider vinegar -- all boiled until the bones crumble.