Prepare the silicone mould (here I use a 4cm diameter * 15-hole mould). Place ice cream in each hole. Flatten the surface, using a spoon. Place in the freezer until it is frozen. I usually make this one day before I want to make mochi.
Once the ice cream is firm, start preparing the mochi mixture : In a microwave safe glass bowl, combine flour and sugar. Stir to combine. Add the water and glucose, mix with an egg beater until smooth. Cover the bowl lightly with cling wrap.
3. Microwave the mixture for 1 minute. Then stir the dough with a spatula. Put it back in the microwave again for another minute and stir lightly. Put it back in the microwave for another 30 seconds (not 1 min) and stir. And once more microwave for 30 seconds and stir. The mixture should be now very thick and translucent.
4. Transfer the mochi dough on your working surface floured with katakuriko/potato starch. As it is very hot you should use a spatula or a dough cuter. Cut the mochi into 15 equal pieces. Don't forget to coat your hand with katakuriko/potato starch.
5. With your hands, take one of these pieces and flatten it into a thick disc. Then put a frozen ice cream ball from the freezer in the middle of the mochi disc. Pull out the cream balls one at a time from the freezer as they will melt quickly. Pull the edges of the dough disc together to cover the cream ball. Press together the edges to seal well. Smoothen the mochi by rolling it on the dusted board.
6. Quickly cover with the plastic wrap and twist to close. Place each mochi ice cream into a cupcake pan or any kind of plate to keep the shape. (Top side down)
7. Put mochi ice cream back into the freezer for a few hours.
8. Keep them outside for a few minutes before you enjoy to make the mochi gets soften a little bit.