Soak dhal for half an hour and then grind it by adding little water.
Take the thick batter and add black pepper, salt to taste, few curry leaves and mix all together.
Heat a pan and add oil. Fry vadas in the oil and keep aside separately.
Take a bowl of water and soak the vadas for few minutes. Then take and press it, so that water drains off.
5)Take the curd in the bowl and mix it well with the spoon adding some water.
Put the vadas into the curd(just soak it). Then sprinkle the cumin powder, salt to taste and chilly powder over the thayir vada. Add some spluttered mustard seeds and curry leaves.