Place flour in medium bowl; rub in ghee. Add seeds; gradually stir in enough of the water to make a firm dough. Knead on floured surface until smooth and elastic, enclose with plastic wrap; refrigerate 30 minutes
2 For the filling, boil, steam or microwave potato until just tender; drain. Mash half the potato in small bowl. Melt ghee in medium saucepan; cook onion, garlic, chilli, ginger, seeds and garam masala, stirring, until onion softens. Stir in coriander, juice and both mashed and chopped potato.
3 Roll dough on floured surface until 3mm (¹/8-inch) thick. Using 8cm (3¼-inch) cutter, cut 28 rounds from dough. Place level teaspoons of cold filling in centre of each round; brush around edge of rounds with water, press together to enclose filling.
4 Heat oil in large saucepan; deep-fry samosas, in batches, until browned and crisp. Drain on absorbent paper.