Beef and pork broth, rice noodles, cabbage, lemongrass, shrimp paste and herbs are the basic ingredients in bun bo hue. Garnishes can include cubes of congealed pig's blood, shrimp balls or slices of brisket.
The base of bun bo hue is an intensely flavored stock made from the shanks, hocks and marrow bones of pork and beef. More flavor is imparted by steeping aromatics such as lemongrass, garlic, onions or shallots in the broth as it cooks. Shrimp paste, a condiment made from dried, fermented shrimp blended with sea salt, adds brininess and a deep flavor of roasted seafood. Annatto chile paste adds color and heat and is usually added to taste. Sugar is added for sweetness in most recipes.
Besides proteins such as brisket, congealed blood and seafood, typical garnishes for bun bo hue include a melange comprised of thinly sliced Thai basil, perilla leaves and rau ram. Some other popular garnishes are thinly sliced yellow onions, lemon or lime wedges, sliced cabbage and scallions.
Like pho, another popular Vietnamese soup, bun bo hue has many variations and can be made with different combinations of spices, meats, herbs and vegetation. Its flavor is described as complex, rich, spicy and soulful.