Yamaguchi Uirō (山口ういろう, warabi starch sweet)

Ingredients

Equipment Needed

• •Nagashi-kan, or a small loaf pan
• •Steamer (mushi-ki), or a wide pot fitted with a rack
• •Clean kitchen cloth for wrapping the steamer lid
• •Fine-mesh strainer
• •Heatproof spatula

Instructions

1. 1

   Prepare the mold

   Line a small nagashi-kan, a rectangular metal confection mold, with parchment, or use a small loaf pan about 8 by 4 inches. Leave a little overhang so the soft uirō lifts out cleanly. Set up a steamer with plenty of water and wrap the lid in a clean cloth so drops of condensation don't mark the surface.

   The cloth under the lid isn't decoration. Water dripping onto the sweet leaves pits and pale spots, and this dish shows every mark.
2. 2

   Mix the slurry

   Put the warabi starch, sugar, and salt in a bowl and whisk them together. Add the cool water a little at a time, whisking until no dry pockets remain. Add the koshi-an and whisk again until the mixture is even, thin, and grayish-purple.

   Cold water gives you time. Hot water would seize the starch before it disperses, and then you're chasing lumps around the bowl like a man who has annoyed his own dessert.
3. 3

   Strain it smooth

   Pass the mixture through a fine-mesh strainer into a heavy saucepan, pressing gently with a spatula. This catches tiny starch lumps and any coarse bits from the bean paste. The finished sweet should feel smooth on the tongue, not sandy.

4. 4

   Thicken gently

   Set the pan over medium-low heat and stir constantly with a heatproof spatula, scraping the bottom and corners. At first it will be thin. After five to eight minutes it will thicken, turn glossy, and leave a soft trail behind the spatula. Stop there. You are only suspending the starch and azuki so they won't settle in the mold; cook it too far and the texture turns heavy before the steamer has done its work.

   This is the detail that decides the dish. Pour the mixture while it is still watery and the starch sinks. Take it to a soft, glossy thickness and the whole log sets evenly.
5. 5

   Fill and cover

   Scrape the thickened mixture into the lined mold while it is still warm. Smooth the top with a wet spatula, then tap the mold once or twice on the counter to settle hidden air pockets. Cover the mold loosely with foil if your steamer lid is not cloth-wrapped.

6. 6

   Steam until set

   Place the mold in the steamer, cover, and keep the water at a steady simmer for 25 to 30 minutes. The uirō is ready when the surface looks glossy and slightly translucent, the center springs back softly, and there are no milky patches. Keep the heat moderate; a hard boil rattles the mold and toughens the edges before the center has settled.

7. 7

   Cool and slice

   Lift the mold out and let the uirō cool to room temperature, then chill it for at least 1 hour so it cuts cleanly. Unmold it, remove the parchment, and slice with a wet knife, wiping the blade between cuts. Serve small pieces, three to a plate if you like the old rule of odd numbers, with a cup of green tea.

Chef Tips

• •Read the label on the starch. Hon-warabiko, pure bracken starch, gives the softest, clearest Yamaguchi character. Many packets sold for warabi mochi are blends of sweet potato or tapioca starch; they work as a sensible stand-in, but the bite will be bouncier and less quiet.
• •Use good koshi-an. If the bean paste tastes flat or overly sweet before it goes in, the finished uirō will taste the same. A plain sweet like this has nowhere to hide.
• •Stir the pan slowly and constantly once heat touches the slurry. Warabi starch thickens from the bottom first, so the corners of the pan are where lumps begin.
• •Don't cut it warm. The log may look set, but the starch gel is still fragile. Cooling is part of the cooking here, and impatience gives you ragged slices.
• •Serve restrained portions. Uirō is soft, sweet, and meant for tea, not for piling high. Leave it room.

Advance Preparation

• •Yamaguchi uirō is well suited to making ahead. Steam it in the morning for evening tea, or make it the day before and keep it tightly wrapped.
• •For the best texture, keep it in a cool room if serving the same day. For longer storage, refrigerate up to 2 days, then bring it back toward room temperature before slicing.
• •Koshi-an can be made several days ahead or bought ready-made. If it is very sweet, reduce the sugar in the recipe by 10 to 20g.

Frequently Asked Questions

Nutrition Information

1 serving (about 90g)