This vibrant Vegan Hot and Sour Soup (Bún Thái) is a masterful blend of sweet, tangy, and spicy flavors, achieved through the perfect combination of pineapple, tamarind, lemongrass, and Thai chili.
The inclusion of mushrooms, tofu, and rice noodles makes this dish both hearty and satisfying while keeping it entirely plant-based.
Authentic Thai Vegan Hot and Sour Soup
Equipment
- 1 large stockpot (6–8 qt)
- 1 Fine mesh sieve
- 1 Chef’s Knife
- 1 Wooden spoon
- 1 Slotted Spoon
Ingredients
Tamarind Juice
- 80 g tamarind pulp ⅓ cup
- 240 ml boiling water 1 cup
Broth
- 30 ml oil 2 tbsp
- 2 tbsp finely chopped lemongrass
- 1 medium tomato sliced
- 170 g pineapple peeled and cut into chunks (≈1 cup)
- 4 –5 cremini mushrooms quartered
- 1.5 liters water 6 cups
- 2 lemongrass stalks slightly crushed
- 50 g granulated sugar ¼ cup
- 3 tsp salt
- 1 tsp mushroom seasoning optional but recommended
- 6 pieces fried tofu
- ¼ Thai chili finely sliced
Add-ins
- Cooked white rice noodles
- Handful of Thai basil
- Vegan bologna or vegan sausages optional
Instructions
- Prepare Tamarind Juice:Tamarind Soaking: Place the tamarind pulp in a medium-sized bowl and pour over 1 cup (240 ml) of freshly boiling water. Allow the pulp to sit for about 10 minutes so it softens and releases its natural tangy flavor.Stir and Break Apart: Using a wooden spoon or spatula, gently press and stir the tamarind to help dissolve it into the water. You want a smooth, rich, tangy liquid without large clumps.Strain the Pulp: Place a fine-mesh sieve over another bowl and pour the tamarind mixture through it. Press down lightly with the back of a spoon to extract as much juice as possible. Discard the remaining pulp. Set the tamarind juice aside; this will be the heart of the soup’s signature sour flavor.
- Sauté Aromatics and Fruits:Heat the Oil: In a large stockpot (6–8 quarts), warm 2 tablespoons of neutral oil over medium heat. The oil should shimmer lightly, indicating it’s ready for sautéing.Add Lemongrass: Add the finely chopped lemongrass and sauté for about 1–2 minutes until fragrant. The aroma should be bright and citrusy, a clear sign that the flavor base is developing.Incorporate Tomato and Pineapple: Add the sliced tomato and pineapple chunks to the pot. Sauté together for 5 minutes, stirring occasionally, until the tomato softens and begins to release its juices, and the pineapple edges turn lightly golden.This step brings out the natural sweetness that balances the soup’s sour and spicy notes.
- Add Mushrooms:Quarter and Sauté: Add the quartered cremini mushrooms to the pot. Stir them gently to coat them in the aromatic mixture. Continue sautéing for 2–3 minutes until the mushrooms soften slightly but still maintain their texture. Mushrooms add a savory, umami depth that enriches the broth.
- Build the Broth:Add Water: Pour 6 cups (1.5 liters) of water into the pot. Stir to combine the sautéed aromatics, fruit, and mushrooms with the liquid.Add Whole Lemongrass Stalks: Lightly crush the remaining 2 lemongrass stalks with the back of a knife and drop them into the pot. Crushing releases additional essential oils, intensifying the soup’s flavor.Season the Broth: Stir in ¼ cup (50 g) granulated sugar, 3 teaspoons salt, and 1 teaspoon mushroom seasoning (optional but recommended). Taste as you go to ensure a perfect balance between sweet, sour, and savory.Incorporate Tamarind Juice: Pour the prepared tamarind juice into the broth and stir well. This addition will bring a signature tang that is essential to authentic Bún Thái.
- Add Tofu and Optional IngredientsInclude Fried Tofu: Carefully add 6 pieces of fried tofu to the simmering broth. Tofu will absorb the flavors of the soup while adding protein and texture.Optional Add-Ins: If desired, add vegan bologna or vegan sausages, as well as fresh greens such as morning glory, green beans, or spinach. These ingredients contribute extra color, nutrients, and variety.
- Simmer the Soup:Bring to a Boil: Increase the heat slightly to bring the soup to a gentle boil.Simmer Uncovered: Reduce the heat to maintain a low simmer and cook uncovered for 25–30 minutes. Stir occasionally to prevent sticking and to help flavors meld. This slow simmer allows the pineapple, lemongrass, and tamarind to infuse the broth fully.Taste and Adjust: Before serving, taste the broth and adjust seasoning as needed. You can add more salt, sugar, or sliced Thai chili for extra heat.
- Cook Rice Noodles:Boil Noodles: In a separate pot, bring water to a boil and cook rice noodles according to package instructions. Traditional round rice noodles are recommended, but flat or thin noodles will also work.Drain and Rinse: Once cooked, drain the noodles and rinse briefly under cool water to prevent sticking. Divide the noodles evenly into serving bowls.
- Assemble the Soup:Distribute Add-Ins: Using a slotted spoon, carefully add tofu, mushrooms, pineapple, and any greens into each bowl on top of the noodles.Pour Broth Over: Ladle the piping hot broth over the noodles and add-ins, ensuring each bowl receives a balanced mixture of all ingredients.Garnish and Serve: Finish with a handful of fresh Thai basil leaves and optional sliced chili on top. Serve immediately while hot, allowing each bite to feature a perfect balance of sweet, sour, spicy, and savory flavors.
Notes
- Use fresh tamarind pulp for the best tangy flavor; bottled juice can be more acidic or concentrated.
- Slightly crush the lemongrass stalks to release essential oils and deepen the aroma.
- Fry the tofu in advance to add texture and prevent it from becoming soggy in the broth.
- Adjust the Thai chili slices to control the soup’s spiciness to your preference.
- This soup is versatile—feel free to add greens such as morning glory, spinach, or green beans for extra nutrition and color.
- Round rice noodles are traditional, but flat or vermicelli noodles also work well.
Nutritionally, it’s a powerhouse: rich in plant-based protein from tofu, high in fiber from mushrooms and greens, and naturally low in saturated fats.
The balanced flavor profile stimulates the palate while providing essential nutrients like potassium, calcium, and iron.
Its quick preparation, minimal cooking complexity, and flexible add-ins make it ideal for everyday meals or batch cooking.
Whether served as a comforting weeknight dinner or a vibrant lunch, this soup delivers warmth, freshness, and wholesome nutrition in every bowl.
Must-Have Tools for Perfect Results
Large Stockpot
Essential for simmering the broth and blending the complex flavors of pineapple, tamarind, and lemongrass.
Its versatility makes it ideal for soups, stews, and large-batch cooking.
Fine-Mesh Sieve
Perfect for straining tamarind pulp and ensuring a smooth, flavorful broth. Beyond this recipe, it’s great for juicing fruits, straining sauces, and dusting powdered sugar.
Chef’s Knife
Precise chopping of vegetables, pineapple, and mushrooms is crucial for consistent cooking and texture. A sharp chef’s knife is invaluable for all kitchen prep tasks.
Wooden Spoon
Ideal for sautéing aromatics and stirring the broth without scratching your cookware. A sturdy wooden spoon is perfect for stirring soups, sauces, and thick mixtures.
Slotted Spoon
Helps scoop tofu, mushrooms, and greens from the broth while leaving excess liquid behind.
Beyond this recipe, it’s perfect for blanching, poaching, and draining cooked ingredients efficiently.
Chef’s Secrets: Unlocking Bold Flavors
The secret to an authentic Bún Thái lies in balancing sweet, sour, and spicy elements.
Fresh lemongrass and tamarind juice create a layered tanginess, while pineapple adds natural sweetness that complements the savory mushrooms and tofu.
Sautéing the aromatics before adding water ensures the flavors develop deeply and meld perfectly.
For an extra umami punch, consider using mushroom seasoning or a splash of soy sauce.
The key is patience during simmering; letting the soup cook slowly allows each ingredient to infuse the broth fully.
Always taste and adjust seasoning gradually to maintain harmony between flavors.
Serving Suggestions: Delicious Presentation Ideas
This soup is perfect as a main course for lunch or dinner.
Serve it in deep bowls with noodles at the bottom, topped with tofu, mushrooms, pineapple, and fresh greens, then pour hot broth over.
Garnish with Thai basil leaves and extra chili slices for a fresh, colorful presentation.
Pair it with light sides such as a cucumber salad or crispy spring rolls to balance the rich flavors of the broth.
For meal prep, store noodles separately and add them just before serving to maintain texture.
Storage Tips: Keep Fresh Longer
Leftover soup can be stored in an airtight container in the refrigerator for up to 3–4 days.
Store noodles separately to prevent them from becoming soggy. Reheat gently on the stove over low heat, adding a splash of water if the broth has thickened.
For longer storage, the broth (without noodles or tofu) can be frozen for up to 2 months.
When reheating frozen broth, defrost overnight in the refrigerator and then simmer gently to revive the flavors.
Frequently Asked Questions
1. Can I make this soup spicier?
Absolutely! Increase the amount of Thai chili slices, or add a dash of chili paste or fresh bird’s eye chilies for an extra kick. Adjust gradually to suit your heat tolerance.
2. Can I substitute tamarind juice?
While tamarind provides the signature sour flavor, you can use a mix of lime juice and a little brown sugar as a last resort. The flavor will differ slightly but still be delicious.
3. What type of tofu works best?
Firm or extra-firm tofu is ideal as it holds its shape when simmered. Lightly frying the tofu first improves texture and prevents it from breaking apart in the broth.
4. Can I make this gluten-free?
Yes! Ensure that any mushroom seasoning, soy sauce, or vegan bologna used is labeled gluten-free.
Rice noodles are naturally gluten-free, making this dish suitable for a gluten-sensitive diet.
5. Can I prepare this soup in advance?
You can prepare the broth and tamarind juice a day ahead. Store them separately and combine with tofu, noodles, and fresh greens just before serving to maintain texture and freshness.
