For every 1 cup of dry lentils, you will need 3 cups of filtered water or stock.
It is advised to take a Dutch oven or a large stock pot to cook the
lentils. Bring the liquid to a boil, add salt and turmeric(optional), and add
washed lentils.
Because lentils swell in size, you must take a pot large enough to hold
them. After the liquid with lentil comes to a boil, reduce the heat to a
simmering temperature and cover tightly to cook the lentils till they are
tender.
Typically, split lentils take 5-7 minutes and whole lentils take 15-20
minutes to cook till soft in stovetop method.
Adding salt while cooking also helps to retain their shape and prevents lentils to become mushy. However, you can always add salt after cooking too.