1-First, begin by blanching the bones. Divide the 10 pounds of beef bones into two large stockpots, cover them with cold water, and bring to a boil. Then, simmer for 15-20 minutes before draining and rinsing the bones to remove impurities. This step ensures a clearer broth with a cleaner taste, setting the foundation for your recipe.

2-Next, preheat your oven to 450°F (232°C) and transfer 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 of celery cut into 2-inch pieces to roasting pans. Make sure not to overcrowd the pans. Roast for 30 minutes, then toss gently and roast for another 15-30 minutes until everything is deeply browned but not burnt.

3-After roasting, wash the stockpots you used for blanching and return the roasted bones and vegetables to them. Use a spatula to scrape any browned bits from the roasting pans and add them to the pots for extra flavor. Now, add the 4 bay leaves, 1/4 cup black peppercorns, 4 whole star anise if using, 2 cinnamon sticks if desired, and 2 tablespoons apple cider vinegar evenly between the two pots.

4-Fill each pot with about 12 cups of cold water, just enough to cover the bones by about one inch. Cover with a lid and bring to a gentle boil. Reduce the heat to low and simmer with the lid slightly ajar, skimming off any foam or excess fat occasionally. Let it simmer for at least 8-12 hours, or up to 24 hours for the best nutrient extraction, adding water as needed to keep the bones submerged. If the vegetables become too soft, you can remove them during this time.

5-Once done, strain the broth through a wire mesh strainer, and if you want it even clearer, strain it again through a fine mesh. Allow it to cool, then remove any remaining meat from the bones for other uses or discard the solids. For storage, cool the broth quickly with ice and refrigerate until the fat solidifies on top, at which point you can remove it if you prefer a lighter version.