Cut each teasel gourd into two halves. Boil potatoes, peal and cut into medium sized pieces.
Take a deep bottomed frying pan, add oil and heat. Add mustard seeds, green chillies and curry leaves.
Fry the ingredients until the onions turn brown. Add the teasel gourd pieces and potato pieces and stir fry for five minutes.
Add salt, turmeric powder and red chilly powder and mix well. Add the tomato pieces and water, put a lid on the pan and allow to simmer in medium flame until the teasel gourd pieces are
cooked smooth.