For the Meatballs:

• 1 lb ground beef (preferably 80/20)
• 1 lb ground pork
• 1 tbsp garlic, minced
• 1/2 cup yellow onion, finely chopped
• 3/4 cup Parmigiano Reggiano, grated
• 1 cup breadcrumbs
• 2 eggs
• 1/4 cup fresh parsley (or 2 tbsp dried parsley)
• 1 tbsp salt
• 1 tsp ground black pepper
• Cooking oil (e.g., vegetable or canola oil)

For the Sweet & Sour Sauce:

• 2 tbsp vegetable or canola oil
• 1 large yellow onion, roughly chopped
• 2 bell peppers, roughly chopped
• 1 tbsp garlic, minced
• 2 tsp fresh ginger, chopped (or 1 tsp ground ginger)
• 1/2 cup soy sauce
• 1/2 cup rice wine vinegar
• 1/4 cup pineapple juice
• 2 tbsp ketchup
• 1/2 cup brown sugar
• 2 cups pineapple chunks (preferably fresh)
• 2 tbsp cornstarch
• 2 tbsp cold water
• 1/4 cup green onions, chopped (for garnish)
• Sesame seeds, for garnish