- Preheat the oven to 180°C.
- Place beef bones on a rimmed baking sheet and roast for 1 hour.
- While the bones are roasting, roughly chop carrots, celery and leeks into 2-3-inch pieces & add the crock pot.
- Cut a head of garlic in half and smash each individual clove of garlic with the side of a knife. Remove the garlic peel and add smashed cloves to the crock pot.
- Top vegetables with roasted bones and add water to cover everything. Leave at least an inch of space to allow for simmering.
- Set crock pot to high and bring to boil. (approximately 4 hours)
- Lower crock pot’s heat and cook for 8-12 hours.
- Use a slotted spoon to remove the leeks, carrots, celery and garlic as best as you can then strain the broth through a mess strainer or cheese cloth into a glass dish or mason jar.
- Let it cool on the counter before topping off with the lid and transferring to the refrigerator (or freezer, if you don’t plan to use/drink within a week)