INGREDIENTS

For the Béchamel Sauce:

4 tablespoons unsalted butter

¼ cup all-purpose flour

4 cups whole milk, warmed

Salt and white pepper, to taste

Pinch of freshly grated ground nutmeg

For the Ragù Bolognese:

2 ribs celery, roughly chopped

2 medium carrots, roughly chopped

1 medium yellow onion, roughly chopped

3 tablespoons extra-virgin olive oil

4 ounces pancetta, finely diced

Salt and pepper, to taste

2 pounds sweet Italian sausage, casings removed

2 fresh bay leaves

2 sprigs thyme

1 cup dry white wine

3 tablespoons tomato paste

3 cups homemade chicken or beef stock (or low-sodium store-bought stock), divided

1 cup whole milk, divided

For the Lasagne:

1 pound lasagne noodles, cooked until very al dente and drained, or no-boil lasagne noodles, uncooked

Unsalted butter, for greasing the dish

1 cups finely grated Parmesan