Bolognese Sauce

Name: Bolognese Sauce
Prep time: 25 min
Cook time: 125 min
Total time: 150 min
Yield: 4 to 6
Ingredients: 2 medium yellow onions, peeled and chopped into 1-inch chunks; 2 carrots, peeled and chopped into 1-inch chunks; 2 celery stalks, cut into 1-inch chunks; 3 cloves garlic, very roughly chopped; 2 tablespoons extra-virgin olive oil; 1⅓ pounds ground beef (85% lean); 4 ounces pancetta, finely diced; 1 teaspoon salt (plus more for pasta water); ½ teaspoon freshly ground black pepper; ½ cup dry red wine; 2 cups beef broth; 1 (14-oz) can crushed tomatoes (about 1¾ cups); ½ teaspoon dried oregano; 1 cup whole milk; 1 pound pasta, for serving; Handful chopped fresh basil or parsley, for serving (optional); Freshly grated Parmigiano-Reggiano, for serving (optional)