Uji Warabi Mochi

Warabi mochi belongs to Uji, the tea town just south of Kyoto, and to the refined sweet-making culture that grew up around the Heian court (794–1185). Bracken starch — warabiko, laboriously washed and settled from the roots of the warabi fern — was a genuine luxury in that era, and a jelly made from it was food fit for aristocrats. The story goes that Emperor Daigo, who reigned in the early tenth century, loved it enough to grant it courtly rank; we file that under tradition, but the underlying point is real. This was a rich person's sweet made from a poor plant, transformed by enormous labor.

The modern honesty problem is the starch. True warabiko is expensive and sets to a translucent, smoky grey with a clean fern-root flavor; most of what's sold as "warabi mochi powder" abroad is sweet-potato or tapioca starch, which makes a perfectly pleasant, whiter, springier jelly that is not quite the same thing. Both are worth making. Just know which you're eating, and don't pay Uji prices for tapioca.

The technique is unforgiving in one spot only — the sudden set over heat — and generous everywhere else. Get the coating of nutty kinako and the pour of dark kuromitsu right, eat it cold on a hot afternoon, and you'll understand why a court thought it worth a rank.