Soak Urad dal for 6 hours. Drain then grind the dal along with the peppercorns into a smooth dough. Add the chopped coriander leaves and chillies. Stir in the salt. In a frying pan heat oil on a medium-high setting. Take a tablespoon full of dough on your palm and make it into little patties with a small hole in middle. Carefully drop them into the hot oil and fry them until they are golden brown. Serve with chutney and sambar.