Korokke Pan (コロッケパン, croquette roll)

Korokke pan is humble food with one proud demand: the croquette must still have a crisp shell when it meets the bread. The roll is soft, the potato is creamy, the tonkatsu sauce is dark and sharp-sweet. If the korokke goes in soggy, the whole sandwich becomes tired before you take the first bite.

The first secret is dry potato. Boil the potatoes in their skins if you can, peel them hot, then mash them while the steam of the cooking water leaves the flesh. Wet potato makes a heavy filling and weakens the crust. Dry potato holds together, tastes clean, and gives you that good contrast against the panko.

This is yōshoku, Japan's old habit of taking Western forms and making them belong at the Japanese table. We tuck korokke into koppepan, a soft long roll, with shredded cabbage and tonkatsu sauce. Nothing fancy. Nothing hidden. The bread should be tender enough to fold around the croquette, but not so sweet that it fights the sauce. If you can't find koppepan, use the plainest soft hot dog roll you can buy, and don't apologize to the sandwich.