Mix the flour and salt in a mixing bowl. Add ghee, rub until fully incorporated and the mixture resembles coarse breadcrumbs. Add yoghurt and 6 tbsp chilled water; knead to make a smooth and pliable dough. Cover with plastic wrap and keep aside for half an hour.

Combine the remaining ingredients except oil in a mixing bowl and knead with hands until well blended. Divide into 18 portions; keep aside.

Divide the dough equally into 18 portions. Shape each portion into a patty. Cover with a damp towel or plastic wrap and set aside.

Flatten each patty into a 2 1/2 inch. or 6.5 cm round. Place one portion of filling in the centre of the dough, then bring the sides of the dough over the filling to enclose completely. Pinch the seams together until thoroughly sealed. Cover with a plastic wrap or a moist towel. Keep aside. Shape and stuff the remaining patties.

Heat the oil in a wok (kadhai) till it starts smoking. Slip in a few patties (seam-side down) at a time. Fry until pale golden in colour and until they sound hollow when tapped. The crust should be delicately blistered and crisp. Drain excess oil and serve hot, accompanied by tomato ketchup.