For the Juicy and Flavorful Meatballs:

• Ground Beef: 1 pound (450g), 80/20 blend recommended. Ground beef forms the base of our meatballs. An 80/20 blend (80% lean meat, 20% fat) is ideal as the fat content contributes to juicy and tender meatballs. If you use a leaner blend, the meatballs might be drier. You can also use a combination of ground beef and ground pork or ground veal for a richer flavor.
• Ground Pork (optional): 1/2 pound (225g). Ground pork adds extra richness and moisture to the meatballs. If using, reduce the ground beef to 1/2 pound. The combination of beef and pork creates a more complex and flavorful meatball.
• Breadcrumbs: 1 cup (100g), plain breadcrumbs. Breadcrumbs act as a binder, helping to hold the meatballs together and absorb moisture, keeping them tender. Plain breadcrumbs are preferred so they don’t compete with the other flavors. You can use panko breadcrumbs for a slightly coarser texture, or Italian breadcrumbs if you want a hint of Italian seasoning, though plain is more traditional for this recipe.
• Milk: 1/2 cup (120ml). Milk is used to moisten the breadcrumbs, creating a “panade,” which helps to keep the meatballs tender and prevents them from drying out during cooking. Whole milk is recommended for richness, but 2% milk will also work.
• Egg: 1 large. An egg acts as another binder, further helping to hold the meatballs together and adding richness. Use a large egg at room temperature for better incorporation.
• Onion, finely diced: 1/2 cup (about 1/2 medium onion). Diced onion adds flavor and moisture to the meatballs. Finely dicing it ensures it cooks through and blends seamlessly into the meatball mixture. Yellow or white onion works well.
• Garlic, minced: 2 cloves. Minced garlic adds a savory and aromatic depth to the meatballs. Freshly minced garlic is always best for flavor.
• Soy Sauce: 1 tablespoon. Soy sauce adds umami and a savory depth of flavor to the meatballs, enhancing their overall taste. Use regular or low-sodium soy sauce, adjusting salt accordingly if using regular soy sauce.
• Sesame Oil: 1 teaspoon. Sesame oil adds a nutty and aromatic flavor that complements the sweet and sour sauce and gives an Asian-inspired touch to the meatballs. Use toasted sesame oil for the most pronounced flavor.
• Salt and Black Pepper: To taste. Salt and black pepper are essential for seasoning the meatballs. Season generously to enhance the flavors of the meat and other ingredients. Freshly ground black pepper is recommended.

For the Classic Sweet and Sour Sauce:

• Pineapple Juice: 1 cup (240ml). Pineapple juice forms the base of the sweet and sour sauce, providing the signature sweetness and a tropical tang. Use unsweetened pineapple juice for the best flavor control, as the sauce will be sweetened with sugar later.
• Rice Vinegar: 1/2 cup (120ml). Rice vinegar provides the essential sour element in the sauce, balancing the sweetness and adding a delicate tang. Use unseasoned rice vinegar. Apple cider vinegar or white vinegar can be substituted in a pinch, but rice vinegar provides the most authentic flavor.
• Brown Sugar, packed: 1/2 cup (100g). Brown sugar adds sweetness and a molasses-like depth of flavor to the sauce. Light or dark brown sugar can be used. Dark brown sugar will result in a richer, more intense flavor.
• Ketchup: 1/4 cup (60ml). Ketchup adds tomato flavor, sweetness, and acidity to the sauce, contributing to its classic sweet and sour profile. Use regular ketchup.
• Soy Sauce: 2 tablespoons. Soy sauce adds umami and savory depth to the sauce, balancing the sweetness and acidity and creating a more complex flavor. Use regular or low-sodium soy sauce, adjusting salt accordingly.
• Cornstarch: 2 tablespoons. Cornstarch is used to thicken the sauce, creating a glossy and smooth texture.
• Water: 2 tablespoons. Water is used to create a cornstarch slurry, which is easier to incorporate into the sauce and prevents lumps.
• Vegetable Oil: 1 tablespoon. Vegetable oil is used for sautéing the vegetables in the sauce, adding flavor and aroma.
• Green Bell Pepper, cut into 1-inch pieces: 1 cup (about 1 medium bell pepper). Green bell pepper is a classic addition to sweet and sour sauce, adding a slightly sweet and slightly bitter flavor and a crisp-tender texture.
• Red Bell Pepper, cut into 1-inch pieces: 1 cup (about 1 medium bell pepper). Red bell pepper adds sweetness, color, and a slightly different flavor profile than green bell pepper. You can use all green bell pepper or all red bell pepper if preferred, or a mix of other colors like yellow or orange bell pepper.
• Onion, cut into wedges: 1 cup (about 1 medium onion). Onion wedges add sweetness and a slightly pungent flavor to the sauce and become tender-crisp as they cook. Use yellow or white onion.
• Pineapple Chunks (canned or fresh): 1 cup. Pineapple chunks add texture, sweetness, and a burst of tropical flavor to the sauce, complementing the pineapple juice base. Canned pineapple chunks, drained, are convenient, or you can use fresh pineapple chunks.