Slow Cooker Bolognese Sauce

Name: Slow Cooker Bolognese Sauce
Ingredients: 1 tablespoon olive oil; 1 medium yellow onion, finely chopped; 2 stalks celery, finely chopped; 1 medium carrot, finely chopped; 2 teaspoons kosher salt, divided; 2 to 3 cloves garlic, minced; 2 tablespoons tomato paste; 1 1/2 to 2 pounds lean ground beef; 1/2 teaspoon dried thyme, or 1 teaspoon fresh thyme leaves; 1/2 teaspoon dried oregano, or 1 teaspoon minced fresh oregano leaves; 1/2 teaspoon freshly ground black pepper; 1/8 teaspoon ground nutmeg; 1 cup whole or 2% milk; 1 cup dry white or red wine; 2 (28-ounce) cans whole peeled tomatoes; 1 bay leaf; Cooked pasta or polenta; Shredded Parmesan cheese (optional)