Heat ghee in a pressure cooker and add cumin seeds. When then begin to change colour, add onions and sauté till transparent.
Add ginger, green chillies and turmeric powder and saute till the onions turn light brown. Add tomatoes and cook till they are soft. Add coriander powder, red chilli powder, dried mango powder, garam masala powder and salt. Sauté till the ghee separates from the masala.
Add the ridge gourd slices and potato cubes and saute for three to four minutes. Add half cup water and pressure cook till two whistles are given out.