I have made this ulundu(in tamil) or udid dal vadais a couple of times, but I never managed to get the proper shape because the batter used to be quite watery. Then my friend suggested me to use wet grinder for grinding the batter as you can use very minimal amount of water during the grinding process and the batter remains quite thick.So after a long time, I made them for the tamil new year. They turned out to be really crisp and delicious.
Soak the dal for 3 to 4 hours. Drain the water completely. Now grind the dal to a smooth paste using a wet grinder preferably. If you dont have one, use a blender/mixer. Please try not to add any water while grinding. Just add a few teaspoons of water if you find it very thick and is difficult for grinding. The batter should be thick and smooth. Try touching the batter with your fingers to ensure that there are no grains.Now add the peppercorns, salt and some pinched curry leaves into the batter and mix well.
Heat the oil for deep frying .Now take a small ball of the batter on your palms(wet your palms so that the batter does not stick to your palms. Flatten it with your fingers and make a hole in the center. You can also make this discs on a wet plastic/polythene sheet. Carefully put this dumplings in hot oil.Fry them on the medium flame so that its well cooked from inside too, till they turn a golden brown.