Wash and soak tuvar dal for 15 minutes. Drain, add fresh water and pressure cook it with little turmeric for 3 whistles or until soft.
Wash, Clean and Chop Paruppu Keerai/Purslane Leaves.
Heat oil given under "Tempering" in a kadai/thick bottomed pan. Splutter mustard seeds, add hing, curry leaves, methi/fenugreek seeds, crushed red chilies and saute for a minute.
Add chopped tomatoes or tomato puree, add 1/2 cup of Water. Add sambhar powder and cook until tomatoes are soft and oil separates.
Add chopped paruppu keerai/purslane leaves and another 1/2 cup of water. Add salt and coconut, mix well.
Let this cook for 10 minutes. By this time, the spinach will be almost cooked, add the soft cooked tuvar dal to this and let it cook for another 10-15 minutes.
After the said time, the sambar would have reached a thick consistency, if not let it sit for another 5 minutes.
When thick gravy consistency is reached, switch off the flame. Serve hot with rice or roti's too, i prefer this delicious gravy with both.