Soak the urad dal for 3-4 hrs.
Drain the water and grind the soaked urad dal in a blender adding salt to a fine thick paste. Add only a very little water, the batter should be thick not watery.
Add 1/2 tsp crushed pepper corns, finely chopped green chillier, ginger, curry leaves and enough salt to the batter.
Heat oil in a deep pan. Make small balls with the battar. The batter will be sticky, so grease the palm of your hands with water and make the balls.
Drop the balls into the hot oil, deep fry it till it turns golden brown in colour.
Transfer it to a kitchen towel and keep it aside. This yields about 20-25 small vadas.
Heat coconut oil in a pan and add onion, green chilly, crushed ginger, curry leaves and little salt. When onion turn light golden in color.
Add the cubed potatoes and saute well.
Add turmeric powder, chilly powder and coriander powder. Saute until their raw smell is gone. Mix well and cook for couple of minutes.
Add thin coconut milk and enough salt. Cover and cook until potatoes are cooked at medium heat.
When they are done, add garam masala powder,black pepper powder and thick coconut milk, a few curry leaves. Bring to a slow boil.
Add the fried vadas and mix well. Check and adjust salt.
Switch off and remove it from heat and keep covered for sometime. The fried vadas will absorb some of the gravy.
Heat another frying pan pour oil, add mustard seeds, (Optional) urad dhal, shallots/small onions, dry red chillies and curry leaves and allow it to splutter. (I have not used urad dhal in this recipe)
Now add the seasoning to the koottu curry.This curry tends to thicken over time.
Serve along with Kerala Sadya or plain rice. Enjoy !