Preheat the oven to 500 degrees Fahrenheit. Line a baking sheet with parchment paper.
In a large bowl, mix together the ½ pound beef mince, ½ pound pork mince, 1 finely minced onion, ¾ cup breadcrumbs, 1 whisked egg, ½ teaspoon garlic powder, ½ teaspoon paprika, ¾ teaspoon salt, and ½ teaspoon pepper.
Scoop the meatball mixture out into 2 tablespoons-sized balls and roll. Place the mataballs on the baking sheet and spray or brush them with a little oil
Bake for 15 minutes, until they are fully cooked, rotating the meatballs halfway through.
In another bowl, whisk together the ½ cup apple cider vinegar, ½ cup pineapple juice, ¼ cup sugar, 2 tablespoons ketchup, 1 tablespoon soy sauce, 1 tablespoon sriracha, 1 teaspoon cornstarch, and ½ cup water.
Once the meatballs are cooked, heat the 2 teaspoons oil in a skillet over high heat and add the ½ cup diced red bell pepper, ½ cup diced yellow bell pepper, and 1 cup diced onion. Cook for two minutes then add the meatballs and sauce.
Reduce the heat to low and simmer the meatballs and vegetables in the sauce. The sauce should start to thicken. Simmer for another 4-5 minutes and remove from heat. Thin the sauce with a little water if required. Serve hot.