This broth is simple and nutritious. The long, slow cooking process draws out the nutrients and minerals from the bones, and the rich liquid enhances anything that it’s added to. You can drink a hot mugful of this as a restorative tonic.
Preheat the oven to 450° F. Put the bones in a roasting pan and roast until well browned, about 30 minutes.
Transfer the bones to a stockpot and add water to cover by 1 inch, then add the onions, celery, carrots and salt. Bring to a boil, skimming any scum that rises to the surface, then lower the heat so the liquid is gently simmering. Simmer for 4 to 5 hours, adding water as needed to keep the bones mostly covered.
Strain through a fine-mesh sieve into a large bowl and let cool completely; skim off any fat that has risen to the surface. Transfer to jars, cover and refrigerate. If storing for more than 4 days, transfer the cooled broth to plastic freezer storage bags and lay flat in the freezer. Frozen broth will keep for up to 6 months.