Natto-Jiru (Natto Soup With Miso, Tofu, and Vegetables)

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.

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.