I first had this dish only after my marriage( as far as I remember) at a friend's place. She had prepared paruppu usili with just all types of paruppu( dhals) and that too frying fully in oil. It tasted real good.
Since paruppu usili is common making with beans or cluster beans(kothavarangai)...here is my version of Beans Paruppu Usili...it came out real good...since this is a dry curry...it is usually served with rice and the main curry might be Mor Kuzhambu or any curries which has no lentils to suit the lunch menu.
Green beans - 1 lb Chopped fine
Onion - 1 small chopped fine
Toor dhal - 3/4 cup
Channa dhal- 1/2 cup
Red chillies - 4 or 5
Jeera/cumin seeds - 1 tsp
Mustard seeds - few
Urad dhal - few
Curry leaves - few
Hing - a pinch
Salt as needed
Oil - 1 tbsp
Wash and soak toor dhal and moong dhal for one hour with water just enough for immersing....later grind coarsely in a mixer with red chillies and cumin seeds...transfer it to idli moulds and steam for about 12 - 15 minutes...remove and crumble with hands...so it powders lightly( or you can transfer it to a pan with little oil and fry in the pan itself...initially it will be sticky...but after few minutes...the water leaves out and it will cout perfect...this way it will be very tasty..but will take long time).
Cook chopped green beans with little water seperately or in a microwave for 8 minutes.
Heat oil in a kadai/pan and add mustard seeds,urad dhal, curry leaves and hing...when they start to splutter up , add chopped onions and fry till light brown... next add the steamed and crumbled paruppu's( dhal) and fry well... next also add cooked green beans and salt...fry together for few more minutes and serve with rice and curry.