Hanoi-Style Bún Riêu (Crab and Tomato Noodle Soup)
A tangy, tomato-rich Vietnamese noodle soup with a light pork and dried-shrimp broth, fluffy crab-and-egg curds, golden fried tofu and springy rice vermicelli. Tamarind gives the broth its signature gentle sourness.
- Prep
- 40 min
- Cook
- 1 hr 35 min
- Wait
- 10 min
- Total
- 2 hr 25 min
- Makes
- 4 large bowls (about 2 L / 8 cups broth plus noodles and toppings)
Steps
Before you start
- Crab paste is sold refrigerated or frozen at Asian markets (look for 'minced crab' or 'crab paste for bún riêu'). Thaw it in the fridge overnight if frozen.
- Pat the tofu very dry with paper towels before frying, otherwise it will spatter hard.
- Read the timing: the broth simmers 60 minutes, so make the topping, tofu and tomatoes while it cooks.
- Wash and arrange all herbs, sprouts and lime wedges on a platter before you cook the noodles so bowls can be assembled while everything is hot.
Blanch the bones
- Put the pork bones in the stockpot and cover with about 8 cups (2 L) of water from the tap.
- Bring to a boil over high heat and boil hard for 5 minutes, until grey foam rises and the water looks cloudy.
- Drain into the sink and rinse each bone under running water to remove scum.
- Scrub out the pot.
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Ready when: Bones are grey-brown with no pink blood clinging to them and the rinse water runs mostly clear.
Tip: Do not skip this step; it is what keeps the broth clear and clean-tasting.
Simmer the broth
- Return the bones to the clean pot with the 2400 ml (10 cups) fresh cold water, onion halves, dried shrimp, rock sugar, 3 tbsp fish sauce and 1 tsp salt.
- Bring to a boil over high heat, then reduce to low so the surface barely trembles.
- Simmer uncovered for 60 minutes, skimming any foam in the first 10 minutes.
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Ready when: Broth is lightly golden, smells sweet and savory, and has reduced slightly to about 8 cups (2 L).
Tip: A hard boil emulsifies fat and makes the broth cloudy; keep it at a gentle simmer.
Mix the crab topping
- While the broth simmers, combine the crab paste, ground pork, beaten eggs, minced shallot, 1 tbsp fish sauce and pepper in a medium bowl.
- Stir in one direction with a fork for about 1 minute until it looks like a loose, evenly mixed paste.
- Let it rest at room temperature while you prepare the other components.
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Ready when: Mixture is uniform with no streaks of egg white and has a loose, spoonable consistency.
Tip: Don't overmix or whisk vigorously; that makes the curds dense instead of fluffy.
Fry the tofu
- Heat 3 tbsp frying oil in the 12-inch skillet over medium-high heat until it shimmers, about 2 minutes.
- Add the tofu in a single layer, standing back from spatters.
- Fry 3 to 4 minutes per side, turning with tongs, until all sides are deep golden and crisp.
- Drain on a paper-towel-lined plate.
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Ready when: Tofu pieces are deep golden brown and feel firm and crisp when tapped with tongs.
Tip: Wipe out the skillet with a paper towel afterward but leave the browned residue; it flavors the tomatoes.
Cook the tomato base
- Heat 2 tbsp cooking oil in the same skillet over medium heat.
- If using annatto, add the seeds and swirl 1 minute until the oil turns deep orange-red, then scoop out and discard the seeds.
- Add the sliced shallots and cook 2 minutes until soft and fragrant.
- Add the tomato wedges and cook, stirring occasionally, 6 to 8 minutes until they soften, release juice and begin to break down.
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Ready when: Tomatoes are soft and slumped, the skins are loosening, and the oil looks red-orange.
Tip: Keep the heat at medium; annatto oil turns bitter if it smokes.
Strain and season broth
- Lift out and discard the bones and onion (or save the meat for snacking).
- Pour the broth through a fine-mesh strainer into a clean pot; the dried shrimp can be discarded.
- Return to a steady gentle simmer over medium-low heat.
- Ladle out ½ cup (120 ml) of the hot broth, stir the tamarind into it until dissolved, then pour it back into the pot.
- Taste and add salt or a splash more fish sauce if needed; it should taste bright, tangy and savory.
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Ready when: Broth is clear golden with a pleasant gentle sourness that does not dominate.
Tip: Season slightly boldly; the noodles and toppings will dilute it in the bowl.
Cook the crab curdsOven 160°F / 70°C
- Add the sautéed tomatoes to the broth and bring it to just below a simmer over medium heat.
- Reduce to medium-low so only tiny bubbles break the surface.
- Spoon the crab mixture into the broth in 8 to 10 heaping tablespoon-sized dollops.
- Do not stir.
- Cover partially and cook 8 to 10 minutes until the dollops set and float to the top as puffy curds.
- Check the pork reaches 160°F (71°C) with an instant-read thermometer in a large curd.
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Ready when: Curds are firm, opaque pink-orange, and floating on the surface; the center of a curd reads 160°F (71°C).
Tip: Stirring or boiling hard before the curds set will break them into crumbs and cloud the broth.
Cook the noodles
- While the curds cook, bring a large saucepan of water to a rolling boil over high heat.
- Add the vermicelli and cook according to package directions, usually 5 to 6 minutes, stirring once or twice to prevent sticking.
- Drain in a colander and rinse under cold water, tossing until the strands are no longer sticky.
- Drain well.
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Ready when: Noodles are tender but still slightly springy and separate easily when lifted.
Tip: Drain thoroughly so excess water does not thin the broth.
Assemble the bowls
- Divide the noodles among 4 large bowls.
- Top each with a few crab curds, tomato wedges and fried tofu using a slotted spoon.
- Ladle about 2 cups (480 ml) of hot broth over each bowl.
- Serve right away with the bean sprouts, herbs, lime wedges, sliced chiles and shrimp paste on the side so everyone can season their own bowl.
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Ready when: Broth is steaming hot and the curds sit on top of the noodles rather than sinking.
Tip: Add shrimp paste sparingly, about ¼ teaspoon at a time; it is intensely pungent.
Good to know
Tips
- Keep the broth at a bare simmer when adding the crab mixture so the curds set whole and fluffy.
- Choose ripe, red tomatoes; underripe ones make the soup taste harsh and need more sugar.
- Tamarind brands vary in sourness, so dissolve it separately and add it gradually, tasting as you go.
- Serve the noodles and broth in separate stages if dining slowly; vermicelli soaks up liquid quickly.
Make ahead
"The broth can be made, strained and seasoned up to 2 days ahead and refrigerated. Fry the tofu up to 1 day ahead. Cook the crab curds fresh in reheated broth for the best texture."
Storage & reheating
"Store broth, curds and tomatoes together in an airtight container in the fridge up to 3 days; store noodles, tofu and fresh toppings separately. Room temperature: no more than 2 hours. Freezer: broth and curds freeze up to 2 months (freeze noodles and tofu separately only if needed; they lose texture). Reheat gently in a pot over medium-low heat until steaming, about 10 minutes, without stirring the curds. Pour over fresh or briefly blanched noodles."
Substitutions
- crab paste (minced crab) → 1 cup (about 170 g) cooked lump crab meat, finely flaked, plus 1 tbsp shrimp paste. Gives a similar sweetness but a flakier, less traditional curd.
- tamarind paste (seedless pulp) → 1½ tbsp fresh lime juice plus 1 tsp sugar, stirred in off the heat. Less deep sourness; add lime at the end so it stays bright.
- pork neck or spare rib bones → 4 cups (960 ml) low-sodium chicken stock plus 6 cups (1.4 L) water. Faster, lighter broth; reduce the simmer time to 20 minutes with the dried shrimp and onion.
- firm tofu → store-bought fried tofu puffs, halved. Skips the frying step; they soak up more broth.