01 - In a large soup pot, combine chicken stock, blanched pork bones, halved onion, smashed garlic, salt, and sugar. Bring the mixture to a rolling boil over high heat, then reduce to medium-low heat and let simmer for 30 minutes to develop a rich, aromatic base. Skim off any foam or impurities that rise to the surface during simmering.
02 - Stir in the fish sauce to deepen the umami flavor. Using a strainer or slotted spoon, remove and discard the pork bones and onion halves from the broth, leaving behind a clear, flavorful liquid.
03 - Add the peeled and deveined shrimp to the simmering broth. Cook for 2–3 minutes until they turn pink and opaque. Remove the shrimp promptly with a slotted spoon and set aside on a plate to prevent overcooking.
04 - Gently add the crab meat and sliced fish cakes to the broth. Simmer over low heat for 5–7 minutes to allow the seafood flavors to meld with the broth. Keep the heat low to prevent the crab from becoming tough.
05 - While the broth simmers, cook the banh canh noodles according to package instructions. Typically, fresh noodles require 2–3 minutes in boiling water, while frozen noodles may take 4–5 minutes. Drain thoroughly and rinse lightly with cool water to stop cooking and prevent sticking.
06 - Divide the cooked noodles evenly among 4 serving bowls. Arrange the cooked shrimp, crab meat, and fish cakes on top of the noodles, ensuring each portion has an equal distribution of seafood.
07 - Carefully ladle the hot broth over the noodles and seafood in each bowl, ensuring all ingredients are submerged. Top with finely sliced spring onions, fried shallots, chopped cilantro, and sliced red chili if desired. Serve with lime wedges and fresh ground black pepper on the side for individual seasoning.