Walnut Yubeshi

Kurumi yubeshi — walnut yubeshi — is a lightly sweet Japanese confection with contrasting textures of firm walnuts in a soft, chewy dough.

Preparation

Roast walnuts at 180°C (350°F) for 7 minutes, or toast lightly in a frying pan. Chop coarsely once done.
If you’re using kurozato in chunk form, chop it into small pieces.
Generously dust a cookie sheet with potato starch or corn starch.

Mix ingredients.
Whisk together the shiratamako and water in a bowl until well blended. Add sugar and whisk until completely blended. Strain mixture through a fine-mesh strainer into a microwave-safe bowl. Stir in walnuts with a rubber spatula.
Cook in microwave.
Cover mixture and microwave on high for 1 minute 30 seconds. Stir well with the spatula. Cover and microwave for another 1 minute 30 seconds. Stir again, until it starts to look a little transparent.
Roll out and cut.
Immediately turn out hot dough onto the prepared cookie sheet and roll out into a roughly 1cm (half-inch) thick sheet. Leave to cool. Once cool, cut into pieces of whatever shape and size you prefer.

It’s important to blend the shiratamako very well, and to strain after blending in the sugar.
Shiratamako is a type of specialty rice flour; you may have to go to a Japanese specialty store to find it.
Kurozato — also called kokutou — is an unrefined Japanese sugar usually sold in large, dark brown chunks. You may be able to find kurozato in asian specialty stores, but it is very similar to much more commonly-available Muscovado or Barbados sugar, which can be substituted; the result is nearly identical. Chunks of kurozato, in addition to being a cooking ingredient, are also sometimes eaten straight, as a kind of candy.