In a large pot or Dutch oven, cook the ground beef and pork over medium heat until browned. Drain off any excess fat.

Add the chopped onion and cook until softened, about 5 minutes. Add the minced garlic and cook for another minute until fragrant.

If using, pour in the red wine and scrape up any browned bits from the bottom of the pot. Let it simmer until mostly evaporated.

Stir in the crushed tomatoes, tomato paste, oregano, basil, red pepper flakes (if using), salt, and black pepper. Bring to a simmer, then reduce heat and cook, uncovered, for at least 30 minutes, stirring occasionally. The longer it simmers, the richer the flavor.

In a medium saucepan, melt the butter over medium heat. Whisk in the flour and cook for 1-2 minutes, stirring constantly, to form a roux.

Gradually whisk in the warm milk, a little at a time, making sure each addition is incorporated before adding more. Continue whisking until the sauce is smooth and thickened.

Bring the sauce to a gentle simmer and cook for about 5 minutes, stirring frequently, until it coats the back of a spoon. Stir in salt and nutmeg (if using).

Preheat your oven to 375°F (190°C).

Spread a thin layer of meat sauce on the bottom of a 9x13 inch baking dish.

Arrange a layer of cooked lasagna noodles over the sauce, breaking them to fit if necessary.

Spread about one-third of the béchamel sauce over the noodles, followed by about one-third of the remaining meat sauce.

Sprinkle with about one-third of the mozzarella and Parmesan cheeses.

Repeat the layering process two more times, ending with a layer of noodles topped with the remaining béchamel sauce and cheeses.

Cover the baking dish tightly with aluminum foil.

Bake for 25 minutes.

Remove the foil and bake for another 20-25 minutes, or until the top is golden brown and bubbly.

Let the lasagna rest for at least 10-15 minutes before slicing and serving.