Veal bones make a particularly rich, gelatinous beef stock. If you don't have them, substitute an equal amount of beef bones. The step of roasting the bones, which imparts fuller flavor, may be omitted if time is short.
To make ahead: Cover and refrigerate for up to 2 days or freeze for up to 6 months.
Nutrition Note: After straining and skimming, broth has negligible calories and nutrients.