How to Make Miso Soup

Pour 4 cups of water into a medium saucepan and drop in a 4 to 6 inch piece of dried kombu. Turn the heat to medium and bring it up to a gentle simmer, no hotter. The kombu starts to expand and rehydrate as the water warms, releasing the umami compounds that give miso soup its savory backbone.

Kombu is dried kelp, thick and leathery, and it does a lot of quiet work here. You'll find it at most Asian grocery stores or in the international aisle of bigger supermarkets. One piece is enough for the whole pot.

While the kombu warms up, put 1 tablespoon of dried wakame into a small bowl and cover it with warm water. Let it sit for about 30 seconds. The dry shreds plump up almost instantly into soft, silky green ribbons.

Drain the wakame in a fine-mesh strainer and set it aside. You'll add it at the very end, after the miso, so it stays tender and doesn't get waterlogged.

As soon as the water reaches a gentle simmer, fish out the kombu with tongs and discard it. Don't let it boil. If kombu goes past a simmer, the broth can turn slimy and a little bitter.

Turn off the heat. Add 1 cup of bonito flakes (also called katsuobushi) to the pot and give them one gentle stir to submerge them. Let them steep off the heat for 3 to 5 minutes. The flakes are thin shavings of dried smoked tuna and they add a gentle smokiness that pulls the whole broth together.

Pour the broth through a fine-mesh strainer set over a clean bowl. The dashi runs through golden and silky while the bonito flakes catch in the mesh. Don't press on the flakes, you'll cloud the broth. Just let it drip.

That clear, light golden liquid is your homemade dashi. Discard the flakes and return the strained dashi to the pot. Set it back over medium heat to keep it warm for the next steps.

Slice about 7 ounces of silken tofu (a little over half a standard block) into bite-sized cubes, around half an inch each. Use a sharp knife and keep the cuts clean. Silken tofu is delicate and will crumble if you push it around too much.

Slide the cubes gently into the warm dashi. Let them sit and warm through for 2 to 3 minutes. You're not cooking the tofu, just getting it hot. Avoid stirring so they don't fall apart.

Scoop 3 to 4 tablespoons of white miso paste into a small bowl. Ladle a bit of the warm dashi from the pot into the bowl and whisk until the miso fully dissolves. You're looking for a smooth, silky slurry without any lumps.

Pour the dissolved miso back into the pot and stir gently to combine. Keep the heat low. Never let miso soup boil after this point. High heat kills the live probiotic cultures in the miso and dulls the flavor.

Add the rehydrated wakame and 2 thinly sliced green onions to the pot. Give it one gentle stir. The wakame plumps a little more in the warm broth and the green onions wake up the bowl with a fresh, slightly oniony bite.

That's the soup. Don't keep it on the heat any longer than needed once the greens are in. Wakame can turn rubbery if it sits too long, and the green onions are best when they keep a little snap.

Ladle the miso soup into bowls and serve it immediately. It's at its best while the broth is hot, the tofu is silky, and the green onions are still bright. Miso soup doesn't sit well, so make it when you're ready to eat.

Serve it on its own as a light meal or starter, alongside a bowl of steamed rice and grilled fish, or with miso salmon for a classic Japanese pairing. Leftovers reheat gently over low heat the next day, but never bring it back to a boil.