Monaka (Crisp Rice Wafers with Bean Paste)

Variations

• Which paste: tsubuan, with the beans left whole, is the default; koshian is sieved smooth; shiroan is made from white kidney beans, and takes matcha well. Chestnut and sweet potato fillings are also common.
• With mochi inside: a piece of grilled mochi tucked in beside the paste sets the crisp shell against something chewy. Confectioners sell this version widely.
• Ice cream monaka: the shell filled with ice cream instead. It solves the sogginess problem by freezing it, which is worth seeing — understand the weakness of the original and it is obvious why this version sells so well in Japanese convenience stores.
• The shape: the name comes from a Heian poem about the moon at its fullest, and the shell was originally round like it. Today the shapes are regional — castles, carp, spinning tops, cherry cocoons. Mooncake is named for the same full moon, so the two share their source.
• Savoury monaka: some places fill them with meat or vegetables as an appetiser. With that much moisture, assembling at the last second is not optional.
• The same bean paste elsewhere: dorayaki, taiyaki, dango, hotteok, songpyeon.
• Alongside: tanghulu.

Tips

• Buy the shells. Making them means rolling glutinous rice dough to paper thinness, drying it and puffing it in a hot iron mould; without that mould the home version comes out thick and leathery. Japanese confectioners commonly buy their shells from specialist makers too. This is the standard practice, not a shortcut.
• Make the paste drier than usual. The one real problem here is water migrating from the paste into the shell, and less water buys more time. A spatula line that holds for a moment is the marker; looser than that and the clock starts running the instant you fill them (thickening sauces).
• Fill at the last moment. Reckon on a couple of hours before the crispness is gone. For guests, bring the shells and the paste separately — which is how they are sold in the first place.
• A soft shell can be brought back. Two minutes in a toaster or a dry pan, stopping just short of colour, drives the moisture off and it crisps again. This only works before filling, so it is the fix for leftover shells (reviving leftovers).
• Do not skip shibukiri. Throwing the first boiling water away is not waste; it is throwing away the tannins in the skins. That single step visibly clears the flavour of the paste (soaking).
• Always add the sugar in stages. All at once, osmosis pulls water back out of the beans and toughens the skins irreversibly. It is the same reason the sugar goes in only after the beans are fully soft (what sugar does).
• Keep the beans under the water. Any that sit proud of it harden in patches and never come right. Top up with hot water as you go.
• A pinch of salt at the end. It does not reduce the sweetness, it sharpens it. One pinch for 180g of sugar; more and the salt arrives first (salt and seasoning).
• Judge the texture cold. Bean paste stiffens another stage as it cools, so paste that seems right in the pan will be stodgy by the time it is filling.
• The paste freezes. Portioned and frozen it keeps a month. Store the shells sealed at room temperature and never in the fridge — the air in there is damp and softens them faster (freezing and thawing).
• Serve it with tea. The sugar runs close to the weight of the beans, and that sweetness was designed around strong green tea being there (serving temperature).