Moong dal, or split mung beans, is available at Indian or Asian groceries. It is quick cooking, and gentle, creamy and satisfying tasting. It can be varied by adding other spices, or by varying the vegetables.
One or more of the following vegetables
Cook the moong dal with the water, the first group of spices and a touch of oil until done, about 45 minutes. Add salt to taste, then cook the cumin seeds in the oil until a darker brown. Add vegetables if desired and saute in the oil, then add to soup.
If you are using spinach, do not saute the spinach first - just add it to the soup after the oil and cook 2-3 minutes before adding lemon juice and serving.