Put the water and agar powder in a saucepan, bring to a boil and leave on medium heat for about 2 minutes. Meanwhile, continue mixing the matcha and white bean paste.
Once the mixture is homogeneous, pour it into the hot water.
Stir well and make sure the mixture dissolves.
Once dissolved, pour it into a mold that you have wet well beforehand. Wait for the mixture to cool and then leave it in the refrigerator for about 2 hours to harden.
Take it out of the pan, cut it into pieces and serve it on a plate. You can then cut it in various ways according to your desires of presentation.