Ingredients:
- 4 lbs beef bones (preferably marrow bones)
- 1 medium onion, quartered
- 2 carrots, chopped
- 2 celery stalks, chopped
- 1 head of garlic, halved horizontally
- 2 bay leaves
- 4 sprigs fresh thyme
- 10-12 cups cold water (enough to cover bones)
- 1 cup dry red wine (e.g., Cabernet Sauvignon or Merlot)
- 2 cups prepared beef stock (from the previous step)
Instructions:
- Preheat the oven to 400°F (200°C) and roast the beef bones for about 30 minutes, turning once until browned.
- Transfer roasted bones to a stockpot, add onion, carrots, celery, garlic, bay leaves, thyme, and cold water to cover; bring to a gentle simmer.
- Reduce heat to low and simmer uncovered for 3-4 hours, skimming impurities regularly.
- Remove from heat, let cool slightly, and strain through a fine-mesh strainer into a clean pot, discarding solids.
- Add dry red wine to the strained stock and bring to a gentle simmer; reduce until the volume is halved, about 30-45 minutes.
- Simmer until thickened and glossy, about 10-15 minutes; allow to cool slightly, then store in an airtight container.