Preparation: 30 minutes, cooking time: 30 minutes, ready in: 1 hour
1. Preheat oven to 190C.
2. Bring a large saucepan of slightly salted water to a boil and cook the macaroni for 8-10 minutes. Drain.
3. Heat the olive oil in a large pan and fry the onions and minced meat until brown and crumbly. Add tomatoes, pepper, nutmeg, cinnamon and bay leaves and simmer for about 5 minutes. Stir in half of the Parmesan.
4. Lightly grease a baking dish with olive oil and fill in the cooked pasta. Cover with the minced meat sauce (after removing the bay leaves).
5. Heat the butter in a small saucepan and stir in the flour. Gradually add the milk and stir until the sauce is almost boiling. Whisk remaining Parmesan and egg yolk in a bowl and pour slowly into the milk sauce, stirring continuously.
6. Pour the sauce over the noodles and bake in the preheated oven for 30 minutes until the surface is golden brown and slightly crispy.