In a Dutch oven over medium heat, crisp pancetta until golden, about 5 minutes. Add onions, carrots, and celery, cooking for another 5-7 minutes until softened.

Stir in ground beef and cook until browned, then add tomato paste and red wine. Allow to simmer for 2.5 to 3 hours on low heat.

While the Bolognese sauce simmers, bring a large pot of salted water to a rolling boil. Add lasagna noodles and cook until al dente, approximately 4 minutes.

Drain and lay the noodles flat on oiled parchment paper to prevent sticking.

In a medium saucepan, melt butter over medium heat. Whisk in flour, cooking for 2-3 minutes until lightly golden. Gradually whisk in warmed milk until the sauce thickens, about 5-7 minutes.

Blend in half of the grated Parmesan and a pinch of nutmeg.

Preheat your oven to 375°F (190°C). In a greased baking dish, ladle béchamel sauce at the bottom.

Layer with lasagna noodles, followed by Bolognese sauce, another layer of béchamel, diced mozzarella, and sprinkling of Parmesan. Repeat layers, ending with béchamel and topping of cheeses.

Cover with aluminum foil and bake for 1 hour. Remove the foil and bake for an additional 15 minutes until bubbly and golden brown.

Allow to rest for 20-30 minutes before serving.