Wash and boil the dals well along with salt and turmeric. The way, I boil my dal, is pressure cook it. After one whistle, lower the flame and cook it for 10 minutes but you can choose to cook it on full too. I think it should be done in 5-6 whistles
Wait for the steam to completely escape. Till than start preparing the tadka or the seasoning.
Heat oil in a pan and add the cumin seeds till they turn a little brown.
Add ginger and garlic and saute for 1-2 minutes.
Add onions and fry till they turn golden brown in color.
Add tomatoes and all the dry masalas except, garam masala at this stage. Saute till the tomatoes are done and start leaving a little oil.
Add the tadka to the dal and boil for 4-5 minutes, add garam masala and boil for 1 minute just to ensure its mixed.
Garnish with fresh coriander leaves and serve hot. According to me, it goes best with tandoori paranthas and bharwan karela but plain rotis and any sabji is as good