Of course, yes. In fact, I first made it as dosai without adding any vegetables. I added fenugreek and made it like regular idli-dosa batter by grinding it in a wet grinder. The batter ferments well, and you can make both idli and dosai. When I made dosai, we felt we could add more vegetables and spice them up. And that's how the idea of adai came, and as it's not fermented, it's easy to make too without prior planning. But of course, you need to soak the lentils, and there is a bit of planning involved.