I had kottu porotta for the first time at a Chettinad restaurant. The kottu was served with a yoghurt raita and some kind of gravy. I asked the waiter how to eat the kottu and he instructed me to pour the yoghurt and the "serwa" on top of the kottu. I liked the serwa and tried to google it in the hope of recreating it at home. I found only one hit that and on the site it said something like "serwa is served on the side with biryani." If you know what this is, can you guide me in the right direction? Is this a broadly cooked gravy or specific to the Chettiyars?