Soak raw rice and whole urad dal separately for 4-5 hours.
Drain water from soaked urad dal and grind with one or two ice cubes to a fine and fluffy batter.
Drain water from soaked rice. Grind rice with minimal water to a coarse paste (Rava or sooji like consistency)
Mix both the batter. Add salt on top (don't mix the salt). Let this batter ferment overnight or for 6 to 8 hours.
Mix the batter well once it is fermented.
In a small frying pan, heat 2 teaspoon oil and prepare a tempering of mustard seeds and split urad dal.
Add this tempering to the batter. Add curd, asafoetida, finely chopped green chillies, roughly pound black pepper, finely chopped ginger, curry leaves, coriander and finely chopped coconut pieces.
Mix the batter well. Do not add water. The batter should be thick, however should be able to pour from a spoon.
Heat oil in a kadai. Using a small round ladle or spoon, pour the vellai appam in hot oil.
Fry vellai appam on medium heat. Flip over once it gets golden from the sides.
Once vellai appam is golden in colour, drain them onto a paper towel. Serve hot with coconut chutney.