Lasagna alla Bolognese

Ingredients

• 12 Fresh or oven-ready lasagna sheets
• 1 tbsp Olive oil
• 1 Onion, finely diced
• 1 Carrot, finely diced
• 1 Celery stalk, finely diced
• 250 g Ground beef
• 250 g Ground pork
• ½ cup Dry red wine
• 400 g Canned crushed tomatoes
• 2 tbsp Tomato paste
• 1 cup Milk
• Salt
• pepper
• 2 tbsp Butter
• 2 tbsp All-purpose flour
• 2 cups Milk
• ¼ tsp Nutmeg
• 1½ cup Parmigiano-Reggiano, grated