Place the beef stock bones, beef marrow bones and chopped veg into a large roasting dish and drizzle with olive oil. Season with the salt and peppercorns and roast in the oven for 20 minutes, until the marrow bones start to melt and turn a golden brown colour
Transfer all the roasting pan ingredients into a large lidded casserole dish and cover with water, add the herbs and apple cider vinegar. Cook in a very low oven for 4-6 hours . Seal the lid of the pot with foil to make sure the water doesn't evaporate
When cooked skim and strain the broth, discarding the veg and bones. Your broth is now ready