Lemongrass Soup with Fermented Tofu Sauce

Bún Xả Chay

3 from 1 reviews

Umami packed soup flavored with lemongrass, lemon leaves, spices, and fermented tofu. Served with rice noodles, fried tofu, and a ton of fresh herbs! A comforting, healthy, and flavorful dish!


  • 2 tbsp (30ml) oil
  • 1 lemongrass stalk, finely minced
  • 2 large tomatoes, diced
  • 4 cups (1 liter) water
  • 1/2 tsp salt
  • 1 tsp sliced cayenne pepper
  • 2 dried shiitakes
  • 34 lemon leaves
  • 1 star anise
  • 2 tsp (6g) coconut sugar
  • optional: 1 tsp tamarind paste soaked in 2 tbsp hot water

Fermented Tofu Sauce

  • 4 cubes fermented tofu*, drained
  • 1/4 tsp sambal badjak (or your favorite chili paste, or minced chili)
  • 2 tbsp (30ml) maple syrup
  • 1 tbsp (15ml) lime juice
  • 1 tsp (5ml) sesame oil


  • 4.5 ounces (130g) rice noodles
  • 9 cubes fried tofu (or sautéed tofu)
  • 1/2 cup (35g) mushrooms
  • fresh cilantro, basil, and green onions


  1. In a large saucepan or pot, heat the oil over medium heat. Once hot, add the lemongrass and sautée for about 3 minutes. Next, add the tomatoes and cook for 7-10 minutes, or until tender.
  2. Add the water, salt, sliced pepper, dried shiitakes, lemon leaves, star anise, and coconut sugar. If using, soak the tamarind in hot water for 10 minutes and add it to the pot.
  3. Bring to a boil, then lower the heat to a simmer and cook for about 20 minutes.
  4. In the meantime, prepare the fermented tofu sauce: in a small mixing bowl, mash the fermented tofu with a fork. Then add the sambal badjak, maple syrup, lime juice, and sesame oil. Mix until combined and set aside.
  5. Prepare the add-ins. Cook the rice noodles according to the package instructions. Sautée or fry the tofu. Slice the mushrooms and the fresh herbs.
  6. To serve, divide the noodles, sliced mushrooms, and tofu into 3 serving bowls. Pour about 1 and 1/2 cup of the broth into the bowls. Next, stir in about 1,5 tbsp of the fermented tofu sauce into each bowl. Top with a ton of fresh herbs and serve immediately!
  7. The broth will keep for up to 3 days in the refrigerator.


* Fermented tofu can be found in Asian stores. It is sold in small jars, the tofu is stored in a very salty brine.

To fry tofu, pat it dry. Cut it into squares and lightly coat it with cornstarch. Heat about one cup of oil in a saucepan. Once hot, add the tofu and fry until it is golden brown, about 5 minutes. Transfer to a kitchen paper towel to remove excess oil.

Adapted from