Wash and cut the pavakkai into medium size pieces or thin slices. Chop the onion and tomato.
Boil two to three glasses of water and when it is boiling put the pavakkai pieces. Allow to cook for five minutes. Do not overcook. Just blanch it. Remove from stove and drain excess water.
In a kadai put the oil and when it is hot, add mustard. When it pops up add urad dhal, jeera, asafetida and curry leaves. Then add chopped onion and fry till it turns transparent. Add tomato pieces along with sambar powder, turmeric powder and salt. Fry till the tomatos are mashed well. Add cooked pavakkai pieces and mix well. Add curry powder. Keep it in low flame for five minutes and stir now and then.
Note: You can also add a tablespoon of tamarind juice and a small piece of jaggery to the curry to get a sour and sweet taste.