Gosh, that makes me feel special!
Making a batch right now.
3 to 4 pounds of bones roasted in a 400 degree oven until browned
Put them in a crock pot add cuttings from veggies (celery and onion and garlic bits) and cover with cold filtered water
Add a splash of apple cider vinegar
Salt and any seasonings you like (I like spike)
Cook on low until the marrow is soft
Strain through a fine sieve
I usually use it 1 part to 3 parts water in soups
Freeze it in ice cube trays