If using fresh tamarind, soak a lemon size ball in warm water for 20 minutes. With your fingers, squeeze out the juice and strain the water. Transfer the clear tamarind water to a vessel. Always use a stainless steel vessel to prepare sambhar. If using tamarind concentrate, then directly add the concentrate and warm water to vessel and give it a good mix till it dissolves. Then add your choice of veggies. I added chopped bell peppers and tomatoes. Also add turmeric powder, sambhar powder, salt, slit green chilly and jaggery. Bring this to a boil on low flame. Meanwhile or even before you do any of the above, boil tur dal in turmeric powder + water. Once its done, add water to it an mash the tur dal well. It should not be runny but like a thick batter consistency. Keep it aside for now. Next step is to prepare the ground masala. Dry roast freshly grated coconut in a pan. You can also use unsweetened coconut flakes or frozen coconut for the recipe. Roast till it turns light golden brown. Then add oil to the pan and roast roughly chopped onions, dried red chillies, chana dal, coriander seeds, urad dal and cumin seeds.