Sweet red bean jelly cake with layers of adzuki and agar is an elegant dessert. A family recipe with naturally sweet, earthy flavor.
In a small saucepan, combine water and agar powder, and whisk off-heat until the agar powder is completely dissolved.
Place the pan over medium heat and stir constantly; once it simmers, reduce to low and cook for 2 minutes until the mixture is clear.
Add sugar and salt, stirring until fully dissolved. Next, fold in the sweetened red bean paste and maintain gentle heat, stirring evenly until smooth.
Pour half of the mixture into a loaf pan lined with plastic wrap, then lightly tap the pan on the counter to remove air bubbles. Let it cool for 10 minutes for a two-layer effect.
Pour the remaining mixture to create the top layer. Cool at room temperature, then refrigerate for 1–2 hours until fully set before slicing and serving.