This is one of my favorite among all the Mochi desserts. I love any desserts or savory dishes make up of yams (aka sweet potatoes in various countries), taro and potatoes. It has a very delicate unique taste and many of the Western culture countries only like certain potatoes and yams but not the Asian culture countries. The East Asian countries have recipes using many different colored yams, taro and potatoes.
It is very common in China, Japan, Singapore, Malaysia and other Southeast Asian countries. It is normally used in baking, roasting, steaming, boiling, drying and frying. The most common and popular ones are in China is sweet potato roasted but in the Winter time you will find the sweet potatoes are being served in sweet soup. Sometime it is being sautéed to a savory dish.
In my family, we normally use the sweet potatoes to make into filling to stuff it in cakes, breads and mochi. Also, we use them in the curry dishes. Today, I am going to use these sweet potatoes as filling in my mochi.
1¼ cups Mochiko (Japanese glutinous rice flour)
¾ cup cornstarch
½ cup + 1½ tablespoons water
¾ cup granulated sugar and ½ cup granulated sugar
3 medium size purple yams (sweet potatoes), peeled and cubed
½ teaspoon purple food color (optional)
Fresh grated coconut with a pinch of salt/desiccated coconut (I preferred fresh)
Heat a Chinese steamer with some water and a 2nd rack with yams cubes (sweet potato cubes) and steam until very tender. Remove the yam/sweet potato cubes in a mixing bowl and mash it until smooth. Stir in the ¾ cup granulated sugar until it completely dissolved. Set aside to cool down.
In another mixing bowl with mochiko flour and the remaining granulated sugar and then stir to combine, then stir in the water and purple food coloring. Cover the mixing bowl with saran wraps and also poke a few small holes on it with a fork. On the microwave set on High Power for one minute, remove and stir to combine with a spatula and then microwave for another one minute more. Stir and microwave another 30 seconds until the mochiko dough is translucent. Once done, add about ¼ cup of mashed purple sweet potato and give it another stir until well combine. Transfer the translucent light purple colored sticky dough onto a floured and smooth flat surface.
Transfer the purplish dough to a floured and smooth flat surface by dusting with cornstarch/tapioca flour/potato starch. Dust your hands and rolling pin generously with cornstarch/tapioca flour/potato starch. Roll out the purplish mochiko dough to a ½ inch thick. Dust lightly a little cornstarch/tapioca flour/potato starch on top of the dough. Cover with Saran wrap/Cling film and chill for 15 minutes.
Remove from refrigerator and lay out on a flat surface. With a round cookie cutter cut all the dough until all surface are used. Drop a spoonful of the filling. Seal it up and roll over the fresh grated coconut or desiccated coconut. Place the coated mochiko into a deep dish with an 1 inch space apart from each piece. Transfer the dish to the refrigerator to chill until serving.