In a large nonstick frying pan put the oil and the cumin seeds.Put the heat on medium.
Add the onion and the hing and stir-fry until the onion is light brown.
Add the serrano chilies, ginger paste, and salt.(You may also add some garlic at this time, especially if you aren’t using the hing.) Stir for one minute.
Add the tomato sauce, ground coriander, sugar and turmeric. Stir to blend.
Drain and rinse the black-eyed peas and add them to the frying pan, along with the one cup water.Bring the mixture to a boil, reduce heat and simmer for about 20 minutes.