Ragu alla Bolognese | America's Test Kitchen

Ingredients

• 1 cup low-sodium chicken broth
• 1 cup beef broth
• 8 teaspoons unflavored gelatin
• 1 onion, chopped coarse
• 1 large carrot, peeled and chopped coarse
• 1 celery rib, chopped coarse
• 4 ounces pancetta, chopped fine
• 4 ounces mortadella, chopped
• 6 ounces chicken livers, trimmed
• 3 tablespoons extra-virgin olive oil
• 3/4 pound 85 percent lean ground beef
• 3/4 pound ground veal
• 3/4 pound ground pork
• 3 tablespoons minced fresh sage
• 1 (6-ounce) can tomato paste
• 2 cups dry red wine
• 1 pound pappardelle or tagliatelle pasta
• Parmesan cheese, grated, for serving