Lasagne al Forno (Italian Beef Lasagna)

Instructions

1. Finely chop the carrot, celery, and onion. Heat the olive oil in a large pan and gently saute the vegetables until softened. Add the beef and pork and cook until browned.
2. Spoon off excess fat if necessary. Add the wine and simmer until reduced by half.
3. Add the passata, tomato paste, bay leaves, 4 cups (1 L) of the stock, salt, and pepper. Simmer uncovered over low heat for 2 1/2 to 3 hours. Add the remaining stock gradually as the sauce reduces.
4. For the white sauce, melt the butter in a saucepan. Stir in the flour and cook for 1 minute. Slowly whisk in the milk until smooth, then cook until thickened. Stir in the nutmeg, Parmesan, salt, and pepper.
5. Heat the oven to 350°F (180°C). Spread a thin layer of ragu in the baking dish. Layer pasta sheets, ragu, white sauce, and mozzarella. Repeat, finishing with white sauce, mozzarella, and a little extra Parmesan if desired.
6. Bake for about 30 minutes, until bubbling and golden. Rest for at least 10 minutes before slicing.