Line a roasting tray with parchment paper and preheat the oven 400f/200c.
Add the bones/meat to a stock pot with water and par boil for 15-20 minutes. During this time you may notice deposits of fatty residue on the surface.
Once the bones have been par boiled, strain off the water in a colander then rinse the bones and blot them completely dry.
Spread the bones, meat, onions, carrots and garlic on the roasting tray then lightly coat with some olive oil.
Roast the bones for about 30-40 minutes or until the meat/bone/vegetables are brown. Keep an eye on any small bones or/and the vegetables to remove them before as soon as they have browned.
Transfer the bones, meat and cider vinegar into the stock pot.
Fill the pot with water, starting with 10 cups. Adding more water when/if the water levels drop too much (you want the finishing liquid to be a few inches below the bones to make 2-3 jars of stock.
Bring the pot to a rolling boil then reduce to a low simmering heat for 6-8 hours with the lid covering the pot (put your pot on the smallest burner/skim off any fat or foam if needed.).
Halfway through the cooking time, add the onion and garlic, carrots, thyme, peppercorns and bay leaves.
Place a cheesecloth (if you have it) inside a large fine mesh strainer (or use the strainer by its self) and carefully pour the mutton stock into the strainer/cloth into a large saucepan/stock pot.
Stir in some dried parsley and pink salt.
Allow to cool down before pour into mason jars or freezer friendly containers.