This paste is then strained — the liquid becoming the base for the soup along with tomato, and the solids used as the basis for crab cakes.

Other ingredients for this dish include tamarind paste, fried tofu, mẻ or giấm bỗng (kinds of rice vinegar), quả dọc (Garcinia multiflora Champ.

), annatto seeds (hạt điều màu) to redden the broth, huyết (congealed pig's blood), split water spinach stems, shredded banana flower, rau kinh giới (Elsholtzia ciliata), spearmint, perilla, bean sprouts and chả chay (vegetarian sausage).

This dish is rich in nutrition: calcium from the ground crab shells, iron from the congealed pig's blood, and vitamins and fiber from the vegetables.

[citation needed] Bún riêu has a fresh sour flavor, so Vietnamese people like to enjoy it in summer.