1. Put the lamb, onions, garlic, oregano, mint, bay 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.

2. Stir in the flour, salt and plenty of pepper. Add the wine, tomatoes, tomato purée and bring to a simmer. Cook for 30 minutes, stirring occasionally, until the lamb is tender and the sauce has thickened.

3. Season with salt and pepper to taste. Set aside.

4. Meanwhile, sprinkle aubergine pieces with salt and set aside for 10 minutes.

5. Rinse the aubergine pieces under cold running water and pat dry in a clean tea towel. Heat 3 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.

6. Cook the potatoes in boiling water for 5 minutes, then drain and cool.

7. Preheat the oven to 160C Fan.

8. Spoon one third of the meat sauce into a deep ovenproof dish. Cover loosely with a layer of potatoes. Repeat the layers twice more, finishing with the aubergines. Pour over the white sauce (see below), making sure it covers in a thick, even layer.

9. Sprinkle with the remaining Parmesan. Bake for 45 minutes, or until deep golden-brown and bubbling.

White sauce:

1. 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 pepper.

2. Remove the saucepan from the heat and allow the sauce to cool. When cooled, stir in the beaten egg.