Prepare and peel the vegetables, then add them to a pot with 8 1/2 cups water (2 liters). Simmer for about 30 minutes to make the broth.

Slice the tofu thinly and fry until golden. Fry the tofu skin until crispy. Chop the leek and sauté until golden.

Using the same oil, sauté the straw mushrooms and shiitake mushrooms (previously cleaned). Season with 2 teaspoons salt, 1 tablespoon soy sauce, 1/2 teaspoon MSG, 1 teaspoon vegetarian bouillon, and 2 teaspoons sugar.

Add the mushrooms to the broth and bring to a boil for a few more minutes, then adjust seasoning to taste.

Blanch the hủ tiếu noodles and place them in bowls. Ladle the hot broth over the noodles, top with crispy tofu skin, and serve with fresh vegetables and herbs.