How to do it
Nowadays, it is easy to buy special oak leaves. You can find it by searching [salted cypress leaves] on tb. Salted leaves can add flavor to kashiwa mochi, but they need to be processed first. Soak the leaves in cold drinking water for about 5 minutes
Take out the leaves and dry them on kitchen paper for later use.
Divide the bean paste into 15g each, roll into balls and set aside. The seasoned bean paste from Akanemaru Honpo brought back from Japan by a friend here is used. Mango and white peach are both very summery flavors. Usually Kashiwa mochi is filled with red bean paste, and the [Kyohi] brand is more recommended. Be careful to buy "red bean paste" instead of "red bean paste". The former has a grainy texture, while the latter is pure bean paste and will be a bit greasy.
Pour 30g of glutinous rice flour into a large bowl, add about 50g of water in small amounts and several times, and mix well with your hands. Note that during this process, the particles of glutinous rice flour should be twisted by hand.
Add white sugar and flour, add the remaining 150g of water one at a time, and mix thoroughly with your hands. Be careful not to have any particles. The glutinous rice balls from the previous step should also be added together.
The batter is a bit thin at this point. Wipe the edge of the basin slightly (to prevent the hard lumps formed on the edge of the basin from falling into the dough after heating and affecting the taste), wrap it in plastic wrap and poke some small holes with a toothpick. Put it in the microwave oven and "bite" it on high heat for 1 minute, take it out and mash it evenly with a spoon while it's still hot. Put it back in the microwave (the plastic wrap can be covered or not at this time), and "beep" on high heat for another 1 minute.
After taking it out, scoop out the dough while it is still hot, pour it on the countertop, and knead it while it is still hot. Knead for about 2 to 3 minutes until it is in place. The result is a smooth and delicate dough. The much darker dough on the left is made with high-gluten flour. Although there is no difference in taste, it is obviously whiter when made with low-gluten flour. Therefore, it is still recommended to use [low-gluten flour].
Roughly divide the cooled dough into 6 portions (each portion is about 60g), dip your hands in some water, and press into a round shape with thin edges and thick middle (like a dumpling wrapper). Place bean paste in the center.
I made two shapes: One is a round shape that is common today, which looks smooth and full, a bit like a bulging wallet. Cute ones are very popular. Wrap the bean filling with dough and roll it into a ball (like making glutinous rice balls), flatten it slightly, wrap it in oak leaves, fold it in half and bring it together.
The other is to put the bean filling in, fold the dough in half and pinch the edges tightly. This approach makes it difficult for the edges to appear neat, and requires some plastic surgery. However, because the gesture of wrapping the bean paste into the dough looks like "putting your hands together to pray", and the kashiwa mochi itself has the meaning of "praying for the safety of future generations", so many old-school people still make it in this shape.