First, wash the ridge gourd. If it is tender, you don't need to remove the ridges. If not, remove them. Then, grate the ridge gourd. You can also chop it into small pieces if you prefer. Do not squeeze the water out of the grated gourd.
Heat oil in a pan. Add mustard seeds and let them splutter. Then, add cumin seeds, asafoetida powder, and curry leaves.
Add chopped onions and saute until they are lightly browned.
Crush the garlic and green chillies together. You can roast the chillies before crushing them, and you can also add a little cumin while crushing. Add this paste to the pan and saute well. You can adjust the number of chillies to your taste.
Add a little turmeric powder, salt to taste, and some chopped coriander leaves. Mix well.
Add the grated ridge gourd to the pan and mix everything together.
Cover the pan and cook for 5-7 minutes.
After 5-7 minutes, the ridge gourd will have released some water. Add the roasted and crushed peanuts and mix well. You can omit the peanuts if you don't like them.
Continue to cook on medium heat, stirring occasionally, until most of the water has evaporated. This should take about 2-3 minutes.
Garnish with more chopped coriander leaves.