Negima-Nabe

Ingredients

• 12⅓ ozTunaBlock of loin, cut into cubes or slices
• 3Japanese leek (naga-negi)cut into 3–5 cm lengths
• 12⅓ ozTofucut into bite-sized pieces; grilled or silken tofu
• 2⅛ cupsDashikombu or katsuo dashi as the broth base
• 3 tbspSoy saucefor seasoning the broth
• 2 tbspMirinfor the broth
• 4 tbspSakefor the broth (optional)
• 1 tspSugarto round off the broth (optional)
• ½ tspSaltfor seasoning the broth (optional)
• 1Kombusoaked in cold water for the stock (optional)
• 1 bunchMitsubacut into 3 cm lengths, added at the end (optional)
• 4shiitake mushroomstems removed (optional)
• 1¾ ozCarrotsliced 5 mm thick, optionally cut into flower shapes
• Spring onionthinly sliced, for garnish (optional)

Method

1. Cut the tuna into bite-sized cubes or slices and keep it cold until you start cooking.
2. Wash the Japanese leeks, trim off the root ends and cut the stalks into 3–5 cm lengths.
3. Cut the tofu into bite-sized pieces. If you like, clean the shiitake and remove the stems, slice the carrot 5 mm thick, and cut the mitsuba into 3 cm lengths.
4. For the broth, soak the kombu in cold water, lift it out before the broth comes to a boil, and use the soaking water as the dashi – or simply have your dashi ready.
5. Bring the dashi to a boil in a pot with the soy sauce and mirin, plus sake, sugar and salt if you're using them.
6. Add the leeks first, then the tuna, tofu and any other vegetables, either laying them in the broth or pouring the hot broth over them.
7. Cook briefly over medium heat, until the fish is just done on the outside, skimming off the foam as it rises.
8. Set the pot on the table and eat from it gradually. Top up with more hot broth as it cooks down, then add the mitsuba at the end and scatter sliced spring onion over the top.

Tips and variations

Instead of a stock cube or katsuo dashi, you can build the broth from kombu-soaking water with sake, mirin, soy sauce, salt and sugar; for something more robust, use ready-made nabe stock cubes based on chicken broth and soy sauce and add shiitake and carrot. One source makes the dish with Shimonita negi from Gunma and uses the green parts as well. The tuna can be cut into 2 cm cubes or sliced thin, and silken tofu can be swapped for grilled yakidōfu – or you can pare everything back to just fish and leek, simmered 5–6 minutes in the seasoned dashi. A shallow pot is nice here: stand the leek pieces upright in it and ladle in hot broth portion by portion.