Preheat your oven to 400F. Roast the marrow bone for 20-30 min, until the marrow in the center of the bone is soft.

Remove bones from the oven and let cool. The marrow is now ready to be scooped out and used. Use the marrow in recipes, spread it on toast, or use the whole bones to make beef stock/bone broth.

Place 2-3 lbs of roasted bones in a large stock pot with a chopped onion, a couple of chopped carrots, a chopped celery stalk, 1 tablespoon salt, 1 tablespoon parsley, and a bay leaf. Cover the mixture with 4-5 quarts of water.

Simmer the mixture for 2-4 hours. Strain the liquid into a large container with a cover and refrigerate the broth overnight.

After refrigerating, the fat will separate and harden on the top of the broth. Pick the fat off of the top of the broth and reserve it for high-heat cooking/sautéing. Strain the liquid again into containers or ice cube trays.

Broth can be stored in the refrigerator for 1-2 weeks or frozen for up to 6 months.