This Japanese soba noodle soup pairs nutty buckwheat noodles with silky tofu, meaty shiitake mushrooms, and tender greens in a light ginger-soy broth. It goes from counter to table in about 25 minutes, and it's the kind of soothing, clean-tasting bowl you'll want on repeat.
Photos by Hannah Kaminsky.
One thing to love about Asian-style soups is that they need very little advance planning. Unlike long-simmered soups that taste even better the next day, this one is at its best the moment it's done. That's especially true of noodle soups: left to sit overnight, the noodles drink up much of the broth, leaving you with more of a noodle dish than a soup. So make it, ladle it, and enjoy it right away. Serve it the traditional way, slurping the noodles from the broth with chopsticks, then using a soup spoon for whatever's left.
Key Ingredients & Substitutions
- Soba noodles. These thin Japanese noodles are made from buckwheat flour, which gives them an earthy, slightly nutty flavor. Many brands also contain wheat flour, so if you need the soup to be gluten-free, look for noodles labeled 100% buckwheat, such as Eden 100% Buckwheat Soba. Udon or thin rice noodles work in a pinch.
- Vegetable broth. A 32-ounce carton is all you need. Choose a low-sodium broth so you can control the saltiness with the soy sauce instead.
- Shiitake mushrooms. Fresh shiitake caps add savory depth to the broth. Remove the tough stems before slicing. Cremini mushrooms are a fine substitute, or use a handful of rehydrated dried shiitake and add a splash of their soaking liquid to the pot.
- Reduced-sodium soy sauce. This seasons the broth. For a gluten-free soup, swap in San-J gluten-free tamari.
- Rice vinegar, sugar, and fresh ginger. A little vinegar and sugar balance the salty soy sauce, and fresh ginger gives the broth its warmth. Use 2 teaspoons of ginger for a gentle bite or 3 if you like it zippy.
- Tofu. Soft tofu melts into the broth for a delicate texture, while firm tofu holds its cubes. Either works, so use what you like.
- Spinach and baby bok choy. Spinach wilts in minutes, and baby bok choy adds a pleasant crunch. Tatsoi or mizuna are lovely alternatives if you find them at a farmers' market.
Helpful Tips
Cook the noodles separately. Soba releases a lot of starch as it cooks. Boiling the noodles in their own pot keeps the broth clear rather than cloudy and gummy, and it lets you control exactly how soft they get.
Rinse the soba after draining. A quick rinse under cool water washes off the surface starch and stops the cooking, so the noodles don't clump together or go mushy by the time they hit the soup. Aim for al dente, since they'll soften a little more in the hot broth.
Keep the simmer gentle. Once the broth comes to a rapid simmer, turn it down and let it bubble quietly. A hard boil can break up the tofu, especially if you're using the soft kind.
Don't overcook the greens. Add the spinach and bok choy near the end and pull the pot off the heat as soon as they wilt. They should stay bright green, which looks better and tastes fresher.
Season at the end. After you add the extra water, taste the broth before serving. A splash more soy sauce or a pinch of sugar can bring it into balance, depending on how salty your broth is.
Variations
- Miso soba soup. Whisk 2 to 3 tablespoons of white miso with a ladle of hot broth, then stir it into the pot after you turn off the heat. For more miso-forward bowls, try this miso-butternut squash soup with soba or udon noodles.
- Spicy version. Add a pinch of red pepper flakes to the broth, or finish each bowl with a few drops of chili oil or a sprinkle of shichimi togarashi.
- Toasted sesame finish. Drizzle each bowl with a few drops of dark sesame oil and scatter toasted sesame seeds on top.
- Extra vegetables. Stir in snow peas, thinly sliced carrots, or bean sprouts along with the greens.
- Crispy tofu topping. Instead of simmering the tofu, pan-fry the cubes until golden and set them on top of each bowl just before serving.
Serving Ideas
With noodles, tofu, and plenty of greens, this soup is filling enough to be a light meal on its own. For a heartier dinner, pair it with a cold noodle salad like this cold soba and cucumber salad, or with some steamed edamame sprinkled with coarse salt.
Smaller portions also make a nice first course before a stir-fry or rice bowl. If you enjoy soba as much as we do, follow up another night with these simple sesame soba noodles.
Storing & Freezing
This soup is best eaten as soon as it's made. If you expect leftovers, store the noodles and broth separately. The broth with its vegetables and tofu keeps in an airtight container in the refrigerator for up to 3 days, and the cooked noodles for 1 to 2 days, tossed with a few drops of oil so they don't stick. Reheat the broth on the stovetop until steaming, then add the noodles just long enough to warm them through. If the noodles and broth were stored together, add a splash of water or broth when reheating to loosen things up.
We don't recommend freezing the finished soup. The soba turns soft and broken, and the tofu and greens get watery after thawing. You can freeze the broth base (broth, mushrooms, and seasonings) for up to 3 months, though. Thaw it overnight in the refrigerator, bring it to a simmer, and add fresh tofu, greens, and freshly cooked noodles.
More Asian-Style Noodle Soups
If you loved this recipe, here are a few more you might enjoy:
- Vegan Ramen Miso Soup
- Easy Tofu Ramen Soup
- 20-Minute Asian Vegetable Noodle Soup
- Rice Noodle Soup with Lettuce and Shiitake Mushrooms
Recipe
Japanese Soba Noodle Soup with Tofu and Greens
Ingredients
- 8 ounces soba noodles use 100% buckwheat soba for gluten-free
- 4 cups low-sodium vegetable broth one 32-ounce carton
- 6 to 8 medium-sized shiitake mushroom caps stems removed, sliced
- 2 tablespoons reduced-sodium soy sauce or tamari for gluten-free
- 2 teaspoons rice vinegar
- 2 teaspoons natural granulated sugar
- 2 to 3 teaspoons minced fresh ginger to taste
- 3 scallions thinly sliced
- 8 ounces soft or firm tofu cut into ½-inch cubes
- 8 to 10 ounces fresh spinach well washed, stemmed, and chopped
- 1 cup chopped baby bok choy or tatsoi or mizuna, optional
- 2 cups water or as needed
- freshly ground pepper to taste
Instructions
- Bring a large saucepan of water to a boil. Break the soba noodles in half and cook according to package directions until al dente. Drain, then rinse briefly under cool water and set aside.
- Meanwhile, combine the vegetable broth, sliced shiitake mushrooms, soy sauce, rice vinegar, sugar, and ginger in a soup pot over medium-high heat. Bring to a rapid simmer, then lower the heat, cover, and simmer gently for 10 minutes.
- Stir in the scallions, tofu, spinach, and bok choy (if using). Cover and cook over medium-low heat until the spinach is wilted but still bright green, about 3 minutes.
- Stir in the cooked noodles and add the 2 cups of water, or enough to give the soup a dense but not overly crowded consistency. Season with pepper and a little more soy sauce if needed. Heat through for a minute or two and serve at once.
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