Wash and pressure cook the bengal gram in a way that it becomes soft and chewable but still being intact.
In the mean time dice the coconut/ potato in to small cubes .
In a pan heat 4 tsp oil and add cumin seeds and split green chillies,bay leaf,dried red chilly.let it fry for half a minute. Then add the coconut/potato cubes and fry untill light brown.
Add to this 1 tsp of roasted cumin powder,turmeric powder,chilly powder,sugar,salt,hing(asefoetida) and fry it for a minute.
Then add the boiled chaana daal or bengal grams into this mixture and stir well.
add 3 - 4 cups of water to this and let the whole thing come to a boil in medium heat. Wait for the coconut/potato to get cooked.
you can add the chopped tomatoes during this time if you want.
After it is cooked properly you add the chopped coriander leaves and remaining roasted cumin seed,garam masala powder for that extra flavour and taste.
Serve hot with poori or paratha.You can also serve it rice if you want.