RE: Fermented Cassava Sandwich

How is the fermented cassava made? Did you make it all by yourself? Did you buy a finished product around that cost? It’s my first time to hear a fermented cassava, but your recipe sounds so interesting to try. I never tasted this kind of toasted bread because my simple idea is just to rub the soft bread with a margarine and preheat in the oven ‘till the surface is brown.