Wash and clean the leak
Roughly chop the top half of the leek and add to the instant pot (or slow cooker)
Roughly chop three carrots and add them too
Now add the bunch of herbs
Place the beef bones on top and cover with water
Lastly add the apple cider vinegar
Pressure cook for two hours, or alternatively over night in the slow cooker
Once cool use a slotted spoon or sieve to take the solidified fat from the top and then strain the vegetables. Discard the vegetables.
Remove the meat from the bones and add back to the broth (discard the bones)