Sweet Potato Yōkan (芋羊羹, Imo Yōkan)

A good satsumaimo needs very little help. When the sweet potato is in shun, at its prime, the flesh is yellow, dense, and sweet enough to make a confection without hiding itself behind bean paste or agar. This is the plainness I like. Nothing hidden.

Yōkan sounds like a difficult sweet because most people think of the glossy bean version set with kanten, or agar. Imo yōkan is simpler. Steam the potato until it gives up completely, mash it while warm with sugar and salt, then press it firmly into a mold. The potato's starch is the setting agent. The first secret is not an ingredient, but patience: steam it until soft all the way through, then press it while warm, before the starch cools and tightens.

The texture should be smooth but not slippery, a firm slice that breaks cleanly under the tooth and tastes first of sweet potato. We serve it in small pieces, often with tea, because wagashi is not meant to shout across the table. Cut three neat bars, leave them room on the plate, and let the color do its work. Honmono is sometimes only the ingredient allowed to stand upright.