It's super easy! This will make lots, but this measurement is the most easy to make. My family loves this amount because it's not too sweet!
Here's another recipe that I learnt from my mother.
This fits perfectly in a 1650 ml tupperware container you can get at a ¥100 store, but will look prettier if you make them in smaller cups! Also try adding peaches, pineapples, or aloe vera.
Enjoy Japanese food around the world.