In a large pot, cook diced pancetta over medium heat until crispy, about 5 minutes. Add minced onion, carrot, and celery, sautéing until softened, around 7 minutes. Incorporate the ground beef and pork, browning for about 10 minutes. Stir in tomato paste, red wine, and crushed tomatoes, along with bay leaves, salt, and pepper. Bring to a simmer, then cover and cook on low for 2.5 to 3 hours, stirring occasionally until thickened.

In a large pot, bring salted water to a rolling boil. Carefully add the egg lasagna noodles, cooking for about 4 minutes until al dente. Drain the noodles and immediately toss with a drizzle of olive oil to prevent sticking. Set aside.

In a saucepan over medium heat, melt 4 tablespoons of unsalted butter. Once melted, whisk in 4 tablespoons of all-purpose flour and cook for 2 to 3 minutes until golden and bubbly. Gradually add 4 cups of warmed whole milk, whisking continuously until thickened, about 5-7 minutes. Integrate a pinch of nutmeg and half a cup of freshly grated Parmesan, stirring until smooth and creamy.

Preheat your oven to 375°F (190°C). Grease a 9x13-inch baking dish. Start layering: spread a thin layer of béchamel sauce, add a layer of noodles, followed by a generous spread of Bolognese sauce, more béchamel, and a sprinkle of mozzarella and Parmesan. Repeat layers, finishing with béchamel and topping with cheese.

Cover the assembled lasagna with aluminum foil and bake for 1 hour. Remove the foil and bake for an additional 15 minutes until the cheese is golden and bubbling. Allow it to rest for 20-30 minutes before slicing.