Mash the banana in a bowl. Preheat the oven to 200℃. Finely crush the walnuts.
Add all ingredients into a bowl and mix well with a whisk.
Pour the dough into a pound cake tin and drop it from a heigh of 2-3 cm to release any air bubbles that may be trapped in the dough.
When the oven is preheated, bake for 25-30 minutes at 200℃. Test the cake with a bamboo skewer. It's done when the skewer comes out clean!
When the cake has cooled, chill for over an hour in the fridge before serving.
Sprinkle some powdered sugar on top, if you'd like.
Story Behind this Recipe
I wanted to make a cake that my vegetarian husband could enjoy. It's my twist on a recipe that I saw in a macrobiotic cookbook.
In this recipe, the kanten dissolves when the cake is baking in the oven and hardens once it cools, so it will still be a bit soft when fully baked. Be sure to chill completely in the fridge before removing from the tin. Use whatever variety of sugar and oil you like.