lasagna bolognese

Ingredients

Bolognese sauce
1 medium onion, coarsely chopped (1-inch pieces are fine)
1 large or 2 slim carrots, coarsely chopped
2 ribs celery, coarsely chopped
3 cloves garlic, coarsely chopped
2 to 3 tablespoons olive oil
Kosher salt
Freshly ground black pepper
2 pounds ground chuck, brisket or round or combination
1 1/4 cups tomato paste (from 2 6-ounce cans)
2 cups red wine, preferably hearty but really, anything you like to drink
Water as needed
2 bay leaves
A few sprigs thyme, tied in a bundle

Béchamel sauce
1/2 cup (8 tablespoons) unsalted butter
1/2 cup all-purpose flour
4 cups whole milk
1 teaspoon table salt
1 clove minced garlic
Freshly grated nutmeg, to taste
Freshly ground black pepper