Baked Spaghetti with Minced Beef and Bacon

Melt butter in a saucepan over medium heat. Stir in the flour and cook, whisking constantly, for about 1 minute.
Gradually pour in the milk, whisking continuously to prevent lumps.
Cook the mixture, stirring constantly, until it thickens. Season with salt and black pepper to taste.
Assemble the Dish:
Preheat the oven to 180°C (355°F).
In a greased baking dish, layer half of the cooked spaghetti, followed by half of the meat sauce, and then a layer of béchamel sauce.
Repeat the layers, and top with grated mozzarella cheese.
Bake:
Bake in the preheated oven for 30 minutes, or until the top is golden and bubbly.