- Stir the rice flour and water together in a bowl until combined. Place the bowl in a bamboo steamer over a pot of gently simmering water, or rest the bowl in a colander that is in a large pot of gently simmering water. Wrap the lid in a tea towel to prevent water from dripping onto the dough, and steam for 20 minutes, stirring the dough halfway.
- Transfer the dough to a saucepan and stir in the sugar, stirring over medium-low heat until the sugar has dissolved and the dough is pliable, 3 to 5 minutes. Stir in pink food colouring as desired.
- Dust a 9-x-13-inch pan with cornstarch/potato starch. Dust a worksurface with the starch and sprinkle a dusting of starch on top of the dough and let this cool for a minute or two, until you can touch it with starchy fingers without it sticking. Rub your rolling pin with starch and gently roll out the dough until it is ¼-inch (6 mm) thick in a rectangle shape (it does not have to fill the pan.) Lift the dough carefully and place it in the pan. Chill for at least half an hour before filling.
- For the filling, stir the red bean paste and freeze-dried strawberries together. Turn the dough out onto a clean worksurface (it’s not fragile at this point) and dust off any excess starch. Use a 2 ½-inch (7.5 cm) round cookie cutter to cut out as many circles as you can. The scraps of dough cannot be re-rolled, but they can be re-warmed (microwave) and reset again, if you wish.
- Use a small scoop or 2 teaspoons to scoop small amounts (just under 1 Tbsp/15 mL) of filling into the centre of each. Holding the circle in your hand, use your other hand to draw up the edges and pinch them together to seal the daifuku. Wiggle the daifuku around to shape it (the bean paste helps it hold its shape) and then set, seam-side down into a paper cup. Repeat with the remaining daifuku. Loosely cover and chill the daifuku until ready to serve.