Preheat the oven to 350°F (175°C).

Cook the penne pasta according to package instructions until al dente. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add the chopped onion and garlic, sautéing until soft and translucent.

Add the ground beef or lamb to the skillet, cooking until browned. Stir in the cinnamon, nutmeg, oregano, salt, and black pepper.

Mix in the crushed tomatoes, tomato paste, and water. Let the mixture simmer for about 10 minutes.

In a separate saucepan, heat the milk over medium heat. Whisk in the flour until smooth and cook until the mixture thickens, stirring constantly.

Remove the sauce from heat and allow it to cool slightly. Whisk in the eggs and half of the Parmesan cheese.

In a large baking dish, layer half of the cooked pasta, followed by the meat sauce, and then the remaining pasta.

Pour the milk mixture over the layers, then sprinkle the remaining Parmesan cheese and the mozzarella cheese on top.

Bake in the preheated oven for 30-35 minutes or until the top is golden and bubbly.

Remove from the oven and let it cool for a few minutes before garnishing with chopped parsley and serving.