To make the pastry, sift the flour and salt together into a large bowl, add the ghee or butter and rub it in with your fingertips until it resembles breadcrumbs. Add enough water to make a stiff dough and knead until smooth. Cover with a damp cloth and set aside while you make the filling.
Put the garlic in a small blender and process until ground to a paste.
Heat the 3 tablespoons ghee over medium heat, add the onions, and stir-fry for about 5-7 minutes, or until golden. Add the garlic, ginger, turmeric and coriander, stir and cook, adding the yoghurt, a little at a time. Season with salt, add the meat and cook for 5 minutes, or until the meat is evenly browned.
Pour in 250ml / 8fl oz (1 cup) water, cover with a lid and cook for 30-45 minutes, or until the mince is tender and completely dry. Stir in the chopped coriander, then remove from the heat and allow to cool completely before using.
To assemble the samosas, pinch off small pieces of dough and roll out thinly on a lightly dusted board or work surface into rounds. Cut each round in half. Dampen half the cut edge with water and fold over the other half to make a cone shape and press firmly to seal.
Hold the cone open in one hand and fill with 2-3 teaspoons meat. Dampen the top edge and seal to enclose the filling. Crimp the edges.
Heat enough ghee or oil for deep-frying in a kadhai or deep, heavy-based pan to 180”C / 35o"F, or until a cube of bread browns in 30 seconds, then reduce the heat.
Working in batches, carefully lower the samosas into the hot oil and deep-fry for about 5 minutes, or until golden on all sides. Remove with a slotted spoon and drain on kitchen paper (paper towels).