To start making the samosa dough or pastry, mix together flour and salt and add ghee. Work the ghee in till it resembles bread crumbs
Cover the dough with a damp cloth and set aside
Crush the coriander seeds, saunf (fennel seeds) and methi (fenugreek seeds) roughly
Add the spices to the pan. Fry the spices till aromatic, then add ginger, garlic and green chilies and stir fry for a minute or two
Add the remaining spices, mashed boiled potatoes and salt.
Use a potato masher to just mash everything together and then mix it
Add the curry leaves right at the end, give it one more good mix and then set the mixture aside to cool
Take a lime sized bowl of dough, roll it between your palms till smooth
Roll it out into a circle which is less than 1 mm thickness and about 6 inches in diameter. Cut the rolled dough in half
Take one edge of the straight side, and place it on the other edge of the straight side in such a way that the dough forms into a cone
Place a tablespoon and a half of the filling in the cone, making sure to fill it only 3/4th of the way
Brush the inside of the unfilled dough with a little water and seal it by pinching the edge together
Heat about 2 inches oil in a pan. Add the samosas to the oil making sure not to overcrowd the pan, and reduce the flame to a simmer
Fry the samosas on a low flame till golden brown on both side. It's important to fry them on a low flame, or the pastry will remain uncooked from inside
Take them out on a plate lined with paper to absorb any extra oil and serve them immediately with ketchup, coriander chutney or tamarind chutney