Prepare the Bolognese Sauce: Heat 30ml (2 tbsp) of olive oil in a large Dutch oven or heavy-bottomed pot over medium heat. Add the finely chopped onion, carrots, and celery (this mixture is called soffritto). Cook, stirring occasionally, until the vegetables have softened and the onion is translucent, about 10-12 minutes. Do not let them brown.

Add the minced garlic and cook for another minute until fragrant. Then, add the ground beef and ground pork to the pot. Break up the meat with a spoon and cook, stirring frequently, until it is browned all over, about 8-10 minutes. Drain off any excess fat.

Pour in the red wine. Bring to a simmer and scrape the bottom of the pot to loosen any browned bits. Let the wine cook down until it has mostly evaporated, about 5 minutes. This deglazing process adds depth of flavor.

Stir in the crushed tomatoes, tomato paste, beef broth, and 125ml (1/2 cup) of whole milk. Add the bay leaf, dried oregano, 15g (2.5 tsp) salt, and 5g (1 tsp) black pepper. Bring the sauce to a gentle simmer.

Reduce the heat to low, cover the pot partially, and let the Bolognese sauce simmer gently for at least 2 hours, or up to 3 hours, stirring occasionally. The longer it simmers, the richer the flavor will become. The sauce should thicken considerably. Remove the bay leaf before assembling the lasagna.

Prepare the Béchamel Sauce: While the Bolognese is simmering, melt 75g (5 tbsp) of butter in a medium saucepan over medium heat. Whisk in 75g (2/3 cup) of all-purpose flour and cook, whisking constantly, for about 1-2 minutes to form a roux. Do not let the roux brown; it should be pale blonde.

Gradually whisk in the 1000ml (4 cups) of warmed milk, a little at a time, ensuring each addition is incorporated before adding more. Continue whisking until the sauce is smooth and starts to thicken, about 5-7 minutes. The sauce should coat the back of a spoon.

Season the béchamel sauce with 1/4 tsp (1g) of freshly grated nutmeg, a pinch of salt, and a pinch of black pepper. Remove from heat and set aside. Cover with plastic wrap directly on the surface to prevent a skin from forming.

Preheat your oven to 190°C (375°F). If using regular lasagna noodles, cook them according to package directions until al dente, then drain and lay them flat on parchment paper to prevent sticking. If using no-boil noodles, no pre-cooking is required.

Assemble the Lasagna: Spread a thin layer of Bolognese sauce (about 1 cup or 250ml) on the bottom of a 9x13-inch (23x33 cm) baking dish. This prevents the first layer of pasta from sticking.

Arrange a layer of lasagna noodles over the sauce, overlapping slightly if necessary. For regular noodles, you'll likely need 3-4 sheets per layer. For no-boil, follow package guidelines.

Spread about 1.5 cups (375ml) of Bolognese sauce evenly over the noodles. Top with about 1 cup (250ml) of the béchamel sauce, spreading it gently.

Sprinkle about 1/2 cup (50g) of grated Parmesan cheese and 1 cup (100g) of shredded mozzarella cheese over the béchamel.

Repeat the layering process: noodles, Bolognese sauce, béchamel sauce, Parmesan, and mozzarella. You should aim for 3-4 layers of pasta, depending on the depth of your dish and the size of your noodles.

For the final layer, top with noodles, then spread the remaining béchamel sauce evenly over the top. Sprinkle generously with the remaining mozzarella cheese and Parmesan cheese.

Cover the baking dish tightly with aluminum foil. Place the dish on a baking sheet (to catch any potential spills). Bake in the preheated oven for 25 minutes.

Remove the foil and continue baking for another 20-25 minutes, or until the top is golden brown and bubbly, and the lasagna is heated through. You can check for doneness by inserting a knife into the center; it should go through easily.

Let the lasagna rest for at least 15-20 minutes before slicing and serving. This allows the layers to set and makes it much easier to cut clean portions.