step 1
Place the aubergine pieces in a colander and sprinkle with salt. Set aside for 10 minutes.
step 2
Put the lamb, onions, garlic, oregano, mint, bay leaves and cinnamon in a large heavy-based frying pan and cook over a medium heat for 10 minutes, stirring with a wooden spoon to break up the meat.
step 3
Stir in the flour, salt and plenty of freshly ground black pepper. Add the wine, tomatoes, tomato purÃÂée and bring to a simmer. Cook for 30 minutes, stirring occasionally until the lamb is tender and the sauce has thickened. Season with salt and freshly ground black pepper to taste. Set aside.
step 4
Rinse the aubergine pieces under cold running water and pat dry in a clean tea towel. Heat three tablespoons of the oil in a heavy-based frying pan and fry the aubergines for 2-3 minutes on each side, adding more oil when necessary. Remove from the pan and set aside to drain on kitchen paper.
step 5
Cook the potatoes in boiling water for five mintues, then drain in a colander under running water until cold.
step 6
Preheat the oven to 180C/350F/Gas 4.
step 7
For the white sauce, melt the butter in a large saucepan and stir in the flour. Cook for a few seconds, then gradually stir in the milk. Add half the parmesan and the grated nutmeg. Simmer the sauce gently for 4-5 minutes, stirring regularly. Season to taste with salt and freshly ground black pepper.
step 8
Remove the saucepan from the heat and quickly stir in the beaten egg. Cover the surface of the sauce with clingfilm to prevent a skin forming
step 9
Spoon one third of the meat sauce into a large, shallow ovenproof dish. Cover with a layer of potatoes and a layer of aubergines. Repeat the layers twice more, finishing with the aubergines. Pour over the white sauce, making sure it covers in a thick, even layer. Sprinkle with the remaining parmesan. Bake in the oven for 45 minutes, or until deep golden-brown and bubbling.