Wash the Bitter gourd well and cut them into small pieces. Heat a pan and add a little cooking oil and brown the sliced onions. Then chopped green chillies , garlic and curry leaves. Then add the bittergourd and stir it well. Now add red chillie powder, curry powder and salt to taste. Finally add thick tamarind juice and cook well.
You can find Bittergourd at Indian stores in the frozen section.