Tuna with Miso-Chile Sauce

This is a more complicated use of miso, useful not only for fish but for meat (just substitute tenderloin for the tuna). I learned it from Japanese-born chef Tadashi Ono, who now lives in New York. His dual lives encouraged Ono to take a few liberties of the type that few would take in Japan, with a classic sauce like this one; but if this is fusion cooking, it’s the good kind.

The Japanese chili paste called tohbanjan is strictly traditional here, but you can use Vietnamese or Kore