Bun Bo Hue

Rinse the beef bones, cover with cold water, bring to a boil and cook for 2–3 minutes, then drain and rinse the bones. Rub the pig's foot, beef shank and pork knuckle with salt.

Heat oil in a large pot, sauté the halved onion and annatto seeds for 1 minute. Add the beef shank and pig's foot, briefly brown them, then pour in water and add the bones, pork knuckle and 3 crushed lemongrass stalks.

Bring the broth to a boil, skim off the foam, add fish sauce, sugar and 1 teaspoon of salt. Simmer uncovered over very low heat for 60 minutes, then remove the pork and continue simmering the broth with the bones and beef for another 60 minutes.

Transfer the pork and knuckle to cold water for 10 minutes, pat dry and let cool. Cool the beef shank as well. Strain the broth, dissolve the shrimp paste in a ladle of hot broth, pour it back through a sieve and season with salt to taste if needed.

For the chili oil, heat oil over low heat with minced garlic, finely chopped lemongrass stalk and chili flakes for 5 minutes, then remove from heat.

Soak the rice noodles in water for 30 minutes, drain, then boil in plenty of boiling water for 10–15 minutes until tender, rinse with cold water and divide among 4 bowls.

Thinly slice the cooled beef shank and pig's foot, and place on top of the noodles along with the pork knuckle, thinly sliced onion, scallions and cilantro. Bring the broth to a boil, pour into the bowls, add bean sprouts, chili oil, lime wedges and fresh chili, and serve immediately.