The Best Italian-American Meatballs | Dinners | Umami

Ingredients

• 1 packet unflavored gelatin (optional, see note)
• 1/2 cup (120ml) homemade chicken stock or low-sodium broth (optional, see note)
• 3 ounces (85g) crustless fresh white bread, cut into 1/2-inch cubes (about 2 unpacked cups)
• 1/3 cup (80ml) buttermilk, plus more as needed
• 1 medium (8-ounce; 225g) yellow onion, minced
• 3 ounces (85g) fatty pancetta, finely minced (see note)
• 2 ounces (55g) Parmigiano-Reggiano, grated, plus more for serving
• 8 medium cloves garlic (about 1 3/4 ounces; 50g), finely minced
• 1/2 cup loosely packed fresh parsley leaves (1 ounce; 30g), minced
• 4 large egg yolks
• 1 teaspoon dried oregano
• 1 teaspoon ground fennel seed
• 1 tablespoon Diamond crystal kosher salt (12g); for table salt use half as much by volume or the same weight
• Freshly ground black pepper
• 1 pound (455g) ground beef (at least 25% fat; see note)
• 1 pound (455g) ground pork (at least 25% fat; see note)
• 5 cups (1.2L) tomato sauce, such as Quick and Easy Italian American Red Sauce, The Best Slow Cooked Tomato Sauce, or The Best Fresh Tomato Sauce