heat oil and add mustard seeds.
Add onion and let them pop up.
Wash bittergourd and apply some salt to it. after 5 minutes wash it again.
When onion turns translucent add chopped bittergourd in to it.
Add salt, turmeric powder, red chilly powder and saute for 5 minutes.
Add tamarind pulp and jaggery and cook till oil oozes.
Serve hot with chapatis.