ULTIMATE GRAVY

Ingredients

• 1 kilogram beef soup bones, or two leftover roast chicken carcasses (see note)
• 2 brown onions, peeled and quartered
• 1 garlic bulb
• 2 carrots, roughly chopped
• 2 tablespoons extra-virgin olive oil
• 1 teaspoon sea salt
• 1 teaspoon freshly ground black pepper
• 5 litres water, plus 4 tablespoons
• 3 sticks celery, roughly chopped
• 2 Bay Leaves
• 4 sprigs of rosemary, divided (or other herbs, see notes)
• 1 teaspoon black peppercorns
• 1 tablespoon apple cider vinegar
• 2 sprigs of rosemary
• 2 tablespoons corn starch
• 1/2 to 1 tablespoon soy sauce, to taste