Ingredients:

  • 4 lbs mixed beef bones (marrow and knuckle)
  • 2 large carrots (200g), roughly chopped
  • 3 stalks celery (150g), including leaves
  • 1 large onion (250g), halved with skin
  • 2 tbsp apple cider vinegar
  • 4 cloves garlic, smashed
  • 1 tsp whole black peppercorns
  • 2 dried bay leaves
  • 1 bunch fresh parsley
  • 14 cups filtered water

Instructions:

  1. Blanch the bones: Place beef bones in a large stockpot and cover with cold water. Bring to a rolling boil for 15 minutes. Drain and rinse the bones thoroughly under cold water to remove denatured proteins and impurities.
  2. Roast for flavor: Preheat oven to 450°F (230°C). Arrange the blanched bones and halved onion on a baking sheet. Roast for 30–40 minutes until deeply browned and caramelized.
  3. Combine ingredients: Transfer the roasted bones and onion into a 12-quart stockpot or slow cooker. Scrape any browned bits from the baking sheet into the pot. Add carrots, celery, garlic, peppercorns, bay leaves, and apple cider vinegar.
  4. Long extraction: Cover with 12-14 cups of filtered water. Bring to a bare simmer (do not boil). If using a slow cooker, set to low. Simmer for 12 to 24 hours, occasionally skimming any fat from the surface.
  5. Final touch and strain: Add the fresh parsley during the last hour of simmering. Strain the broth through a fine-mesh sieve lined with cheesecloth. Discard solids and cool the liquid rapidly in an ice bath before refrigerating.