Heat oil in a wok & fry the kathal till they just change colour. do not cook or over fry them.
Remove the oil and add 2-3 tbsp fresh oil & heat oil on high heat.

Once oil is hot add onions & saute for 5-7 minutes till light brown.
Add ginger & garlic & saute till medium brown.

Add tomato puree & stir well. Add all spices & salt & stir again.

Add the kathal. Reduce heat to low, mix well & cover with a lid. Let it cook.
Check every 3-4 minutes. Stir & cover again.

Repeat this till kathal is soft & done.

If cooking in a pressure cooker then just add 1/2 cup water and cook for two whistles. Open lid and let it cook nicely till water evaporates.

Garnish with green coriander and serve hot!