Place powdered gelatine in a microwave-safe bowl, add the water and set aside to steep. Blend the banana, Plus Koji Koji-Amazake Base and lemon juice with a stick blender or in a blender until smooth.
2.
Whip the cream to thicken. Stop whipping just before reaching soft peaks. Add to the banana mixture and stir to combine.
3.
Microwave the steeped powdered gelatine at 500W for 20 seconds, then quickly add to the mousse mixture, stirring constantly.
4.
Once well combined, pour into a container, cover and refrigerate for two hours until set. Using a spoon, place large scoops of mousse into serving dishes, and sprinkle with cocoa powder or nuts to taste.
