When the steaming broth is ladled into the bowl, the eye of round cooks and the onion and scallions lose their raw edge. The broth can be made up to one month ahead; remove the brisket and let the broth cool to room temperature before freezing. Wrap the brisket tightly in plastic, store it in a resealable freezer bag, and freeze it; thaw completely in the refrigerator before slicing.
In classical French cooking, brown stock is made with veal bones for a delicate-bodied soup; here, beef is added for a deeper flavor. To make a traditional version, simply replace the beef with more veal bones. This recipe is from the "Martha Stewart's Cooking School" cookbook.
In Vietnam, pho, as this rice-noodle soup is known, is often enjoyed for breakfast. Nutritionists recommend incorporating red meat into one's diet just as it's used here -- in small portions and as a complement to other foods. The soup also includes bean sprouts and a handful of fresh herbs. The stock needs to be refrigerated for at least six hours; make it a day ahead.