Boil the pasta in plenty of salted water according to the package directions until al dente. Drain, return to the pan, toss with the butter, and allow to cool slightly before mixing in the grated graviera or Gruyère cheese.

For the meat sauce, heat the oil in a large saucepan over a medium heat. Gently cook the onion until soft and translucent. Increase the heat, add the meat and stir constantly until browned and the liquid has evaporated. Season with salt, pepper and oregano, pour in the wine and simmer until the alcohol has cooked off. Stir in the tomatoes, parsley and sugar, reduce the heat and cook gently for 30 minutes, adding up to 120ml (½ cup) water if it becomes too dry.

To make the béchamel, melt the butter in a saucepan over a low heat, add the flour (add the extra tablespoon if you like a thicker topping) and stir for 5–6 minutes. Gradually whisk in the milk, starting with a couple of cups until thickened slightly, then adding the rest. Cook for another 1–2 minutes, season with the salt and nutmeg, then let cook for 5–10 minutes, stirring occasionally. Beat in the eggs, one at a time, mixing well after each addition, until smooth and glossy.

Preheat the oven to 160°C fan/180°C/350°F/Gas mark 4.

Butter a 33 × 23 × 8cm (13 × 9 × 3¼in) ovenproof dish. Layer half of the pasta on the base, spread the meat sauce evenly over, top with the remaining pasta, then pour over the béchamel so it completely covers the pasta.

Run a fork lightly through the surface, so the sauce seeps into the pasta. Sprinkle with the grated Parmesan and a little pepper.

Bake for 35–40 minutes until golden brown. Allow to rest for at least 15 minutes before slicing and serving.