Peel and slit the potatoes and onions but do not separate them into pieces. For stuffing mix scraped coconut, chopped coriander leaves, half a teaspoon of red chilli powder, quarter teaspoon of turmeric powder, coriander powder, garam masala powder, salt, lemon juice and one tablespoon oil. Mix and put this stuffing in the potatoes and the onions.
Heat the remaining oil, add cumin seeds, remaining red chilli powder and turmeric powder and immediately add one to one and a quarter cups of water. Add potatoes, bring it to boil and simmer for ten to fifteen minutes. Add onions and cook for another ten minutes and serve hot.