- 3 pounds beef bones, or more to taste
- 3 carrots, chopped
- 2 stalks celery, chopped
- 1 onion, chopped
- 5 cloves garlic, smashed
- 1 teaspoon whole black peppercorns
- 2 bay leaves
- cold water to cover
- 2 tablespoons apple cider vinegar
- kosher salt to taste
- Preheat oven to 375 degrees F (190 degrees C). Line a baking sheet with aluminum foil; spread beef bones out on prepared baking sheet.
- Roast bones in the preheated oven until browned, 25 to 30 minutes.
- Place carrots, celery, onion, garlic, peppercorns, and bay leaves in a slow cooker. Place roasted bones over vegetables; pour in enough cold water to cover bones. Add apple cider vinegar and kosher salt.
- Cook on Low for 8 hours. Pour broth through a fine-mesh strainer into a bowl and discard any strained solids.