1-Start by blanching the bones, as this step removes impurities for a clearer broth. Divide 10 pounds of beef bones between two large stockpots, cover with cold water, bring to a boil, and simmer for 15-20 minutes before draining and rinsing.

2-Next, roast the blanched bones along with the vegetables 4 large carrots chopped into 2-inch pieces, 2 medium onions quartered, 2 whole heads of garlic halved crosswise, and 6 stalks celery cut into 2-inch pieces in a preheated oven at 450°F (232°C) for 30 minutes.

3-After roasting, toss them gently and roast for another 15-30 minutes until well browned, which caramelizes the bones and vegetables to enhance flavor. Transfer everything back to clean stockpots, scraping the brown bits from the roasting pans into the pots for added taste. Add 4 bay leaves, 1/4 cup whole black peppercorns, 4 whole star anise (if using), 2 cinnamon sticks (if using), and 2 tablespoons apple cider vinegar, then pour in about 12 cups of cold water to cover the bones by an inch.

4-Bring the mixture to a low boil, reduce heat to low, and simmer with the lid slightly ajar for 8-12 hours, or up to 24 hours for deeper flavor skim foam or fat as needed and add water to keep bones submerged. Once done, strain through a fine mesh strainer or cheesecloth, let it cool, remove any remaining meat from the bones for later use, and optionally refrigerate to skim off solidified fat.