Ingredients:

  • 4 lbs beef marrow and knuckle bones
  • 2 tbsp avocado oil
  • 2 large carrots, roughly chopped
  • 2 stalks celery, roughly chopped
  • 1 large yellow onion, quartered
  • 1 head of garlic, halved crosswise
  • 2 bay leaves
  • 2 tbsp apple cider vinegar
  • 12 cups filtered cold water
  • 1 tbsp whole black peppercorns

Instructions:

  1. Preheat your oven to 400°F (200°C). Toss the beef bones in oil on a baking sheet and roast for 30–40 minutes, turning occasionally until they are a deep, mahogany brown.
  2. Transfer the roasted bones into the slow cooker. Add the chopped carrots, celery, onion, garlic, bay leaves, and peppercorns.
  3. Pour in the apple cider vinegar and cold water until the bones are just covered. Cover with a tight lid and set to LOW for 24 hours.
  4. Turn off the slow cooker and let it cool slightly. Carefully strain the liquid through a fine mesh strainer lined with cheesecloth into a large bowl.
  5. Squeeze the vegetables to extract every last drop of nutrient-dense liquid and discard the solids.