Why This Recipe Works
- Whisking broth into both the miso pastes and natto before adding them to the main pot of soup ensures they melt in fully and don't clump.
- Crushing the natto in a suribachi (or other mortar and pestle, or even just with a fork) ensures it incorporates into the broth more fully.
Loaded with tender vegetables, mushrooms, seaweed, and tofu, and flavored with two kinds of miso and natto (fermented soybeans), this hearty soup is deeply savory and nourishing.
Natto, fermented soybeans, are a staple in traditional Japanese cuisine. To make natto, soybeans are cooked for many hours, then inoculated with bacteria and left to ferment in a temperature-controlled fermentation room (about 100 to 120°F). After a day or so, the soybeans are cooled to room temperature and placed in the refrigerator to mature for a few hours.
The finished natto are stored and sold in styrofoam containers, complete with little packets of soy sauce and hot mustard. To enjoy, you simply mix the natto with the mustard and soy sauce, and serve with rice.
Though a fresh packet of natto looks innocuous at first glance, a brief stirring brings out the strands of slimy, fermented mucilage that covers the soybeans. It's a texture that can be a challenge for some, though it's one worth learning to love (if you don't already). One good step towards building an appreciation of natto is to eat it in dishes like this warming soup, where its slimy texture is largely lost in a creamy, miso-flavored broth.
"I've never understood the hullabaloo about natto."
But really, I've never understood the hullabaloo about natto. Many delicious items are just spoiled food in disguise: salami, cheese, yogurt, and so forth. When carefully controlled, taking a food item past its prime does wonders for flavor and texture, and natto is a great example of that. There's nothing better than a piping hot bowl of rice with a pile of slimy soybeans on top. Add a few pickles and a bowl of miso soup, and you've got a delicious peasant meal in ten minutes or less.
Natto, in fact, is an excellent addition to miso soup. Some recipes for natto miso soup call for rinsing the soybeans in cold water before adding them to the dashi, but I think that doing so defeats the purpose of putting natto in the soup. The slightly bitter tang of natto complements the savoriness of a brown miso and counters the sweetness of a lighter, sweeter white miso.
Happily for natto lovers everywhere, the product is readily found in Japanese markets. Look for the stacks of little styrofoam boxes next to the tofu and konnyaku.
May 21, 2010
This recipe was cross-tested in 2022 and updated to guarantee best results. We increased the dashi and dried wakame, added root vegetables, and pounded the natto into a paste so it would still lend deep flavor to the soup—but not overpower it with its texture. The broth is now whisked into both the miso and the natto to help loosen them up before they're stirred into the soup.
Natto-Jiru (Natto Soup With Miso, Tofu, and Vegetables)
In this recipe for natto miso soup, the bitter tang of natto complements both brown miso and lighter, sweeter miso.
1 cup mushrooms, such as shiitake, shimeji, or enoki
5 cups (1.2L) dashi
1 cup mixed vegetables, such as carrot, daikon, and lotus root
1/4 cup (12g) dried wakame seaweed
1/4 cup (1.8 ounces; 50g) natto, see note
2 tablespoons (34g) chogo/awase (mixed) miso or brown rice miso
2 tablespoons (34g) shiromiso (sweet white miso)
1/2 block silken, medium, or firm tofu (8 ounces, 227g), cut into 1/2-inch cubes (about 1 cup)
Sliced scallions, for garnish
Prepare mushrooms (this will vary depending on the type): wash away any dirt, discard tough stems, slice shiitake caps and any other large mushroom caps, and separate mushroom clusters into manageable groups. Meanwhile, in a medium saucepan, bring dashi to a simmer over medium-high heat. Add vegetables and mushrooms, cover, and reduce heat to medium-low. Simmer until tender, 8 to 10 minutes. Uncover, stir in wakame, and remove soup from heat.
In a suribachi (or mortar and pestle), grind natto into a paste that is mostly smooth and very sticky; alternatively, place in a small bowl and mash with a fork.
In a small bowl, combine mixed miso (or brown rice miso) and sweet white miso and whisk in 3 tablespoons (45ml) hot dashi broth until smooth and free of lumps, then stir miso into soup until well combined. Whisk 2 tablespoons (30ml) hot dashi broth into natto paste to loosen, then stir into soup. Gently stir in cubed tofu.
Serve immediately, garnished with scallions.