In a 8x8 microwave safe glass container, mix together 3/4 cup glutinous rice flour, 1/2 cup sugar, 3/4 cup water, and 1 drop of vinegar. Note: The vinegar makes the bingsu tteok soft & chewy. You will not taste it.
Mix until smooth, do not leave any lumps.
Cover with plastic wrap and microwave for 4 minutes. The time may vary depending on the strength of your microwave, so keep an eye on it.
Remove the plastic wrap and let it cool completely.
Dust the top with some potato starch.
Pry the sides off of the glassware using a spatula, then pull it out and dust the other side with potato starch.
Cut into strips, then into cubes.
Dust every piece in potato starch so that they are not sticky on the outside anymore. Shake off the excess and store in an air tight container for up to 3 days.
Cut the strawberries, kiwi, and banana into small pieces.
Shave 2 cups of ice using a coarse setting. If you don't have an ice shaver, you can use a food processor. Pulse until the ice is shaved to your desired consistency.
Drizzle half of the condensed milk over the shaved ice
Top with sweet red bean, fruits, bingsu tteok, and the rest of the condensed milk.
Serve right away- you can mix it up like this or eat it as is. I always mix mine :)