Prepare the Bolognese Sauce:

Make the soffritto:

1. In a large sauté pan, melt the butter over medium heat. Add the pancetta, onion, celery, and carrot. Cook until the onion turns pale gold and the vegetables are softened.

Brown the meat:

1. Add the ground beef, pork, and sausage to the pan. Increase the heat to high and cook until the meat is browned. Season with ground clove, cinnamon, and black pepper.

Add the tomatoes:

1. Stir in the chopped or canned tomatoes and bring the mixture to a gentle simmer. If using canned tomatoes, break them up as they cook.

Simmer with milk:

1. Add the milk and season with sea salt. Reduce the heat to low and simmer for 2½ hours, stirring every 20 minutes. If the sauce thickens too much and begins to stick, add ¼ cup of water and continue cooking until it reaches a rich, thick consistency.

Prepare the Béchamel Sauce:

Heat the milk:

1. In a small saucepan, warm the milk over medium-low heat until almost boiling.

Make the roux:

1. In another pan, melt the butter over low heat. Add the flour and whisk rapidly to form a smooth paste. Cook for 1 minute, stirring constantly, then remove from heat.

Combine the milk and roux:

1. Gradually add half of the warm milk to the roux, whisking continuously until smooth. Return to low heat, add the remaining milk, and stir until the sauce thickens. Season with a pinch of sea salt and continue whisking until no lumps remain. Remove from heat.

Prepare the Lasagna:

Cook the noodles:

1. Preheat the oven to 375°F. Boil the lasagna noodles in salted water for 8 minutes or until al dente. Drain and lay them flat on clean kitchen towels to prevent sticking.

Assemble the layers:

1. Lightly grease a 13x9-inch baking dish with olive oil. Spread a thin layer of Bolognese sauce on the bottom. Layer noodles over the sauce, slightly overlapping each sheet.
2. Add one-third of the remaining Bolognese, one-third of the béchamel, and a sprinkle of Parmesan cheese. Repeat the layering process two more times. Finish with a final layer of noodles, béchamel, and Parmesan on top.

Bake the lasagna:

1. Cover the dish with aluminum foil and bake for 25–30 minutes, or until the top is lightly browned and bubbling.

Rest and serve:

1. Remove from the oven and allow the lasagna to cool for 10 minutes before slicing and serving.