Cook pasta in a large pan of boiling salted water until just tender; drain.

Meanwhile, heat the oil in a large heavy-based saucepan over medium heat; cook onion and garlic, stirring, until soft but not coloured. Add the mince; cook, stirring, over a high heat until browned. Add the cinnamon and nutmeg; cook, stirring, for 1 minute. Add the tomato paste; cook, stirring, for a further minute. Stir in the undrained tomatoes, sugar and salt and pepper to taste. Simmer, uncovered, for about 10 minutes or until the liquid has reduced. The mixture should be quite dry and very rich and fragrant. Now is the time to taste and adjust seasoning if necessary.

Melt the butter in a large saucepan over a medium heat; stir in the flour. Stir for about 1 minute or until frothy. Gradually stir in the milk; cook, stirring, until mixture boils and thickens. Season to taste with salt and pepper. Remove from the heat; whisk in the eggs.

Preheat the oven to 200°C (180°C fan-forced). Place pasta and the meat mixture in the base of a 20cm x 30cm ovenproof dish, then spread with the white sauce. Sprinkle the top with parmesan.

Place dish on an oven tray. Bake for about 30 minutes or until the top is golden and bubbling. Serve with green salad, if desired.