Scrape the skin of potol/parwal and make 3 or 4 slits on the sides without breaking them.
Marinate them with some salt and turmeric powder for 10 minutes
In a heavy bottomed pan, add 1 tablespoon oil
Shallow fry the parwal till they become brown. Drain and keep aside.
In the same pan roast the bayleaf, cloves and cardamom
Add the onion paste and fry for 2 more minutes.
While onion is frying, mix chilli, coriander, cumin, garam masala powders, enough salt, ginger garlic paste and khus khus paste (if using) in a small bowl with ¼ cup water to make a paste
Add the paste to the onion and fry for few more minutes.
Add the parwal and mix well till the masala coats parwal
Add ½ cup water and cook for few minutes. Adjust the seasoning.
Mix the curd and jaggery, beat well and add to the vegetables.
Cook further on a slow flame, till potol becomes soft and coated well with the gravy