This sweet potato and tofu soba is so savory, satisfying, and the perfect unfussy dinner for a cold night.
A perfect vegan cold-weather meal, this sweet potato and tofu soba will warm you right up.
Soba is one of my favorite noodles. I love its earthy, nutty flavor, and it works so well with a savory, salty broth. This recipe combines a salty, slightly spicy broth with earthy soba, umami-rich mushrooms, and the natural sweetness of sweet potatoes for a soup you’ll crave all the time. Tofu adds protein, although a shredded rotisserie chicken or fried ground pork would also be nice.
As I continue to build out more plant-based recipes (here and on Exploring Vegan), this dish has become a go-to example of how comforting vegan food can be. The sweet potatoes soften into the broth, the tofu soaks up all that flavor, and the soba noodles make it feel hearty and complete. It’s simple, flexible, and exactly the kind of recipe you can tweak based on what you have on hand.
Whether you’re fully vegan or just looking to add more meatless dinners into your rotation, this one is delicious, and one that meat-eaters and vegetarians can both enjoy.
How to make sweet potato and tofu soba
An umami-rich noodle soup with tender sweet potatoes, silky tofu, and buckwheat soba noodles in a savory sesame-soy broth.
What you need
- Broth vegetables and aromatics: Shallot, shiitake mushrooms, and sweet potato
- Broth flavoring: Tamari, mirin, sesame oil, and chili oil create a salty, sweet, nutty, and slightly spicy broth.
- Firm tofu: Gives this soup its protein, though chicken or pork would also be good.
- Dry soba noodles: I love soba for their earthy, nutty flavor, but try it with ramen, udon, or rice noodles.
- Finishing touches: I serve this with sliced scallions, but you can finish with sesame seeds or your favorite furikake seasoning.
How to make it
Step 1: Sauté the shallot.
Heat the neutral oil in a soup pot over medium heat. Add the diced shallot and cook for about 5 minutes, until soft and translucent.
Step 2: Cook the mushrooms and sweet potato.
Add the sliced shiitake mushrooms and cook for 5 minutes, stirring occasionally. Add the sweet potato cubes and season with the kosher salt. Sauté for another 3 to 4 minutes to lightly soften the vegetables and build flavor.
Step 3: Simmer the broth.
Pour in the water or vegetable stock and bring to a boil. Reduce the heat to low, then add the tamari, mirin, sesame oil, and chili oil. Gently add the tofu, cover the pot, and simmer for 20 to 30 minutes, until the sweet potatoes are fork-tender.
Step 4: Adjust seasoning.
Remove the lid and taste the broth. Adjust with additional mirin, tamari, sesame oil, or chili oil as needed to balance sweetness, saltiness, and heat.
Step 5: Cook the soba.
Bring a separate pot of water to a boil. Cook the soba noodles according to package directions, about 4 to 5 minutes. Drain and rinse well. Divide the noodles among four bowls.
Step 6: Serve.
Ladle the hot soup over the noodles and garnish with sliced scallions, if using. Serve immediately.
FAQ
Can I make this gluten-free?
Yes. Use certified gluten-free soba (100% buckwheat) or substitute rice noodles, and make sure your tamari is gluten-free.
Can I add more vegetables?
Absolutely. Bok choy, baby spinach, napa cabbage, or snow peas all work well added in the last few minutes of simmering.
How spicy is this?
It’s mildly spicy as written. Adjust the chili oil up or down depending on your heat tolerance.
Storage and Reheating
Storage:
Store the broth, vegetables, and tofu separately from the soba noodles if possible. Transfer everything to airtight containers and refrigerate for up to 4 days. Keeping the noodles separate helps prevent them from becoming overly soft.
Reheating:
Reheat the soup gently on the stovetop over medium-low heat until warmed through. Add a splash of water or vegetable stock if the broth has reduced. Warm the soba noodles separately in hot water for 30 to 60 seconds, then drain and add them to the hot soup just before serving.
Make-ahead tip:
This soup is an excellent make-ahead option. The flavors deepen as it sits, making leftovers even better the next day!
Sweet Potato and Tofu Soba
Equipment
- 2 Large pots
Ingredients
- 1 tablespoon neutral oil
- 1 shallot (peeled and diced)
- 8 ounces shiitake mushrooms (caps thinly sliced; stems removed and discarded)
- ¾ pound sweet potato (peeled and cut into 1-inch cubes)
- 6 cups water or vegetable stock
- 1½ teaspoons kosher salt (plus more to taste)
- ¼ cup tamari
- 2 tablespoons mirin
- 1 tablespoon sesame oil
- 1 tablespoon chili oil (more or less to taste, depending on spice preference)
- 1 pound firm tofu (patted dry and cut into 1-inch cubes)
- 8 ounces dry soba
- 2 scallions (thinly sliced; optional for garnish)
Instructions
Sauté the shallot:
- Heat 1 tablespoon neutral oil in a soup pot over medium heat. Add the shallot and sauté for 5 minutes until translucent.
Cook the mushrooms and sweet potato:
- Add the shiitake mushrooms to the shallot and cook, stirring occasionally, for 5 minutes. Add the diced sweet potato and season with 1½ teaspoons kosher salt. Sauté over medium heat for an additional 3 to 4 minutes.
Simmer the broth:
- Add 6 cups of water to the pot and bring to a boil. Reduce the heat to low. Add ¼ cup tamari, 2 tablespoons mirin, 1 tablespoon sesame oil, and 1 tablespoon chili oil. Add the cubed tofu and cover the pot. Simmer for 20 to 30 minutes or until the sweet potatoes are fork-tender.
- Remove the lid from the pot and taste the broth. Add more tamari, mirin, sesame oil, or chili oil depending on your preference. If you feel the broth is too salty, you can add a few splashes of water to dilute it.
Cook the noodles:
- Bring a large pot of water to a boil. Add the dry soba and cook for 4 to 5 minutes until tender. Drain and rinse. Divide the noodles between 4 bowls.
To serve:
- Ladle the soup over the noodles. Garnish with sliced scallions. Enjoy!
