The magic of idli, dosa, uttapam and appe is that you can soak any combination of lentil, portion of rice, grind and ferment it properly. And you can get infinite variety of snack items. The only thing is you should know if the combination will taste good or not. When your kitchen counter is stocked with the lentils which you have bought from store and you want to finish them as soon as possible because lentils usually go bad if kept for a long time, you can use them to make soft idlis, crispy dosas, healthy appes or crunchy onion uttapas.