Wash the papdi bean pods thoroughly, string them, and then separate each pod in two pieces. My mom tells me this should be done before cutting the beans to ensure there aren't any worms in the beans.
Cut the pods in approx. one inch pieces. Retain the beans, don't throw them away. Peel and cut the potato in cubes.
Heat oil in pressure cooker, add onion n saute till it done brown in color. Add tomatoes n cook till tomatoes get soft.
Add salt, red chilli powder and garam masala powder, mix it well.
Add papdi n potatoes, mix it. Cover the lid and pressure cook it on 3whistles. Wait until air release from pressure cooker.