Nama Yatsuhashi (Steamed Cinnamon Rice Sheets Folded over Bean Paste)

Name: Nama Yatsuhashi (Steamed Cinnamon Rice Sheets Folded over Bean Paste)
Prep time: 30 min
Cook time: 20 min
Total time: 50 min
Yield: 4 servings
Cuisine: Japanese
Ingredients: 70 g non-glutinous rice flour; 30 g glutinous rice flour; 50 g sugar; 110 ml water; 1 tsp ground cinnamon; 1 tsp ground cinnamon; 2 tbsp kinako (roasted soybean flour); 160 g smooth red bean paste

Kyoto's cinnamon sweet. A dough of non-glutinous rice flour with a little glutinous flour is steamed whole, kneaded, rolled to 2mm under a dusting of cinnamon, cut into squares and folded into triangles over bean paste. The rule that a rice dough cannot be folded is about a dough that is mostly raw; in this one all of the starch has been cooked, so it rolls thin and folds without cracking. The same dough dried out in the oven is the original, hard yatsuhashi.

Ingredients

4servings

Dough
non-glutinous rice flour · dry-milled; Japanese joshinko is closest70 g
glutinous rice flour · shiratamako is closest30 g
sugar50 g
water110 ml
ground cinnamon1 tsp
Dusting and filling
ground cinnamon1 tsp
kinako (roasted soybean flour)2 tbsp
smooth red bean paste · in 16 pieces160 g

Steps

Mix the two rice flours and the sugar in a bowl and stir in the water a little at a time to a thick, smooth batter.
Line a steamer with a damp cloth, pour the batter in, spread it level and steam over high heat for 20 minutes. It is done when it has gone translucent right to the middle.
⏲ 20 min
Lift it out in the cloth, tip the hot dough into a bowl and work it with a wet wooden spoon, pressing and folding, for 3-4 minutes until smooth and glossy. Add 1 tsp cinnamon and keep working until it is evenly mixed.
⏲ 4 min
Mix the cinnamon and kinako and dust the worktop generously. Put the dough down while it is warm, dust the top and roll it out 2mm thick.
Trim the edges and cut into 7cm squares. You should get about 16.
Put a piece of bean paste on each square and fold it corner to corner into a triangle. Just press the edges lightly with a fingertip; the dough is tacky enough that nothing else is needed to hold it.
Brush off the loose dusting and plate them. Eat them the same day. Keep any left over wrapped at a cool room temperature, never in the fridge.

Tips & Variations

Variations

Baked yatsuhashi: Korean Wikipedia describes yatsuhashi as a kind of senbei with a characteristic cinnamon flavour, and says it was originally called katayaki senbei, a hard-baked cracker. Roll the same dough thinner, to 1mm, cut it into rectangles and bake at 150°C for 20-25 minutes until bone dry, and you have that hard form.
Without the filling: the article sorts it three ways — baked yatsuhashi; nama yatsuhashi, the dough cooked but not baked; and an-iri nama yatsuhashi, the same with bean paste inside. Serve the squares stacked and unfilled and that is nama yatsuhashi.
Other flavours: matcha worked into the dough in place of the cinnamon turns it green.
History: nama yatsuhashi was devised after the Second World War and is now more popular than the baked kind, per Korean Wikipedia, and yatsuhashi is Kyoto's best-known souvenir.

Tips

Steam the whole dough. Rice flour has no gluten. In dango's words, "The tack created when boiling water gelatinises the starch is the only adhesive there is". Khanom chin goes further: "This one can only be extruded, because rice has no gluten and so a rice dough cannot be stretched or folded at all." And it gives its way of holding that dough together: "Boiling a fifth of the dough first is the pivot." Yatsuhashi cooks not a fifth but all of it. The whole dough is held by gelatinised starch, so it rolls to 2mm without tearing and folds corner to corner without cracking. Khanom chin's sentence is not wrong: for a dough that is mostly raw it holds, and this dough has no raw part left (steaming).
A little glutinous flour goes in. Dango divides the work between the two flours: "Joshinko (non-glutinous) supplies the bite, shiratamako (glutinous) the chew." All non-glutinous flour goes the other way — firm and prone to cracking. In a dough that is rolled thin and folded, a crack is the failure, so this one is 70 non-glutinous to 30 glutinous. Push the glutinous flour higher and, as dango says, you are heading for mochi.
Roll it while it is warm. Steamed rice dough firms as it cools, and dango gives the reason: "Rice starch retrogrades, and the fridge is the worst place for it because that is the band where it happens fastest". Get the rolling, cutting and folding done while it is still warm.
Eat them the same day, and keep them out of the fridge. Daifuku puts a number on the difference between the two flours: "Ordinary short-grain rice is around 17 per cent amylose; glutinous rice is effectively zero." The molecule that recrystallises as it cools — which is what staling is — is the straight one. Nama yatsuhashi is mostly non-glutinous rice, so it firms as it stands. The baked form has no such problem: its water has been driven off, so there is nothing left to firm up.
Dust with cinnamon and kinako. Raw rice flour as a dusting leaves uncooked flour on the outside. Cinnamon and kinako are eaten as they are, so the dusting becomes part of the taste.