2 tablespoons extra-virgin olive oil
2 onions, finely chopped
2 pounds ground lamb or beef
1 can (8 ounces) unseasoned tomato sauce
1 can (6 ounces) tomato paste
1 cup water
1/2 teaspoon ground cinnamon
1/2 teaspoon dried oregano
Salt and freshly ground black pepper
Pinch sugar, or to taste
1 pound tube-shaped pasta, such as penne
3 tablespoons butter
1/4 cup unbleached all-purpose flour
3 1/2 cups milk
3 eggs, beaten
Freshly grated nutmeg
1 1/2 cups freshly grated parmesan