Heat the oil in a saucepan.Test the heat by adding one cumin seed to the oil; if it cracks right away it is ready.
Add the asafetida, black mustard seed and cumin seed. After seeds are cracked add bay leaves, paprika, and turmeric.
Stir for a second and add sliced tomatoes and green chili.
Cover the pan after mixture comes to boil and let it cook for 6 to 7 minutes on low medium heat; tomatoes should be soft but still be in slices.
Mix the cornstarch with 2 teaspoons of water and add to the tomatoes (corn starch is added to give thickness to gravy but this is optional).
Let chutney cook for another minute. Add sugar and cilantro, close the heat and cover for few minutes.
Adjust the salt, sugar and pepper to your taste.