The most important thing about cooking dal is the phorons or spices used for flavouring it. Different dals will have different combinations for phorons and the same dal can have several different phorons, depending on the mood of the cook. The first step for all dals, though, is always the same: boiling in water until it is soft and soupy, the amount of water needed varying widely, depending on how thin or how thick you want your dal to be. My family thought of lentils as a rather thick potage with long slices of onion and green chillies and, of course, a sweetish undertaste, so when I first went to live in Bangladesh with my husband, I was very disconcerted at seeing the thin dal that appeared on my in-laws’ table. The taste was different too, for the lentils had been flavoured with minutely chopped onions and garlic, together with bay leaves and dried red chillies, all fried in oil.
In summer the common dals in our home are moong and kalai rather than lentils, yellow split peas or pigeon peas. And while in winter the moong dal may be roasted in a frying pan before cooking, in summer it is preferred kancha or unroasted, because it is easier to digest and does not heat the system.