In a bowl, mix glutinous rice flour and sugar.
Gradually add water while stirring to avoid lumps.
Transfer the mixture to a microwave-safe bowl.
Cover with plastic wrap and microwave for 1 minute.
Stir the mixture, then microwave for another minute.
Repeat until the mixture becomes sticky and slightly translucent.
Dust a clean surface with cornstarch.
Pour the mochi dough onto the cornstarch and let it cool slightly.
Roll the dough into a thin sheet and cut into squares.
Place a scoop of ice cream in the center of each square and fold the edges over to seal.
Roll into a ball and dust with more cornstarch.
Freeze for at least 2 hours before serving.