Yuzu Koshō (柚子胡椒, yuzu chili paste)

Yuzu koshō looks like something bought in a tiny jar by people who know a secret. The secret is short. Green yuzu peel, fresh green chili, and salt, pounded until the citrus oil and chili heat become one paste. It isn't difficult. It is only seasonal.

The one thing that decides it is the peel. Use firm green yuzu in early autumn, while the rind is still sharp and fragrant, before the fruit turns yellow and softer in character. Grate only the colored skin, not the white pith beneath it, because the pith brings bitterness without aroma. We want the bright oil in the peel and nothing dull hiding under it.

Salt does more than season here. It draws moisture from the chili and peel, tightens the paste, and lets it age safely for a few weeks in the refrigerator. That rest matters. Freshly pounded yuzu koshō is loud, all elbows and opinions; after time, the heat settles and the citrus deepens.

Set out a little dish beside nabe, grilled chicken, grilled fish, or a bowl of udon. Use less than you think. This is not a sauce to bury food under. It is a clear, hot accent, honmono by restraint.