Preparation

1. Preheat oven to 400°F. Line large, rimmed baking sheet with parchment paper.
2. Arrange beef bones, onion, celery, carrots and garlic in single layer on prepared baking sheet. Drizzle with olive oil. Season with salt and pepper.
3. Roast in preheated oven 45 minutes, turning once. Transfer roasted meats and veggies, along with any juices, to 6-quart stock pot or Dutch oven. Sprinkle with thyme and parsley. Add bay leaf, vinegar and enough water to cover.
4. Bring mixture to low boil over medium-high heat. Reduce heat. Simmer as long as possible for the best flavor, at least 3 hours.
5. Remove large pieces with a slotted spoon. Strain broth through fine sieve or cheesecloth. Cool to room temperature. Transfer to freezer-proof quart-size containers. Refrigerate overnight.
6. Use a spoon to skim fat from surface. Keep broth in refrigerator up to 4 days or freeze for later.