1.Melt ghee in large frying pan; cook lamb, stirring, until browned. Add onion, garlic and spices; cook, stirring, until onion is soft.
2.Add undrained crushed tomatoes, the water, paste and mint; simmer, uncovered, about 20 minutes or until sauce is very thick.
3.Meanwhile, cook pasta in large saucepan of boiling water, uncovered, until just tender; drain. Toss pasta in large bowl with oil. Place half the pasta into 2.5-litre (10 cup) shallow ovenproof dish, top with sauce, then remaining pasta. Pour combined egg and juice over pasta; sprinkle with cheese.
4.Bake, uncovered, in moderate oven about 40 minutes or until heated through and cheese is browned lightly.