Classic Baked Lasagna Bolognese (Lasagne alla Bolognese) Recipe

Ingredients (9)

• 4 tablespoons unsalted butter (2 ounces; 60g), plus more for greasing baking dish
• 4 tablespoons all-purpose flour (1.25 ounces; 35g)
• 3 cups (700ml) whole milk
• Kosher salt and freshly ground black pepper
• Pinch freshly grated nutmeg
• 2 pounds (900g) fresh homemade plain egg or spinach pasta or store-bought fresh lasagna noodles, or 2 (450g) boxes dry lasagna noodles (see note)
• Vegetable oil, for greasing pasta
• 1 1/2 quarts (1.5L) warm ragù bolognese (choose either this classic slow-cooked version, this extra-rich oven-baked version, or this pressure-cooker version)
• 3 ounces (85g) Parmigiano-Reggiano cheese