Marinate the Pork: In a bowl, combine the pork pieces with water, soy sauce, sesame oil, onion powder, and garlic powder. Stir until the liquid is fully absorbed. Allow the pork to marinate for 30 minutes.
Prepare the Sauce: Heat 1 teaspoon of oil in a small saucepan over medium heat. Add the ginger slices and star anise, sautéing until fragrant and lightly caramelized (about 1 minute). Stir in the ketchup and cook until it deepens in color, approximately 2 minutes. Incorporate the vinegar, sugar, and pineapple juice, stirring well. Let the sauce simmer on low heat for about 30 minutes until it thickens slightly and coats the back of a spoon. Once ready, set it aside for later use.
Heat the Oil for Frying: Pour 3 cups of oil into a small pot and heat to 350°F (175°C). Using a smaller pot minimizes excess oil waste. Once the oil reaches the correct temperature, maintain it for even frying.
Coat the Pork: In a shallow dish, mix the flour, cornstarch, salt, and black pepper. Dredge the marinated pork in the flour mixture, dip it into the beaten egg, and coat it again with the flour mixture to create a crispy exterior.
First Fry: Fry the pork in batches for 2 to 3 minutes, or until golden brown. Transfer to a wire rack or paper towel-lined plate to drain excess oil.
Second Fry for Crispiness: Reheat the oil and fry the pork a second time for added crunch. This ensures the coating remains crisp even after being combined with the sauce.
Stir-Fry the Vegetables: In a clean wok or large skillet, heat 1 tablespoon of oil over medium-high heat. Add the bell peppers and onions, stir-frying for about 30 seconds.
Combine the Ingredients: Pour the prepared sauce into the wok along with the pineapple chunks. Bring to a gentle simmer. Stir in the cornstarch slurry, adding half first and stirring for 15 seconds before deciding whether to add more. Keep in mind that the sauce will thicken further as it cools.
Adjust the Sauce Flavor: Taste the sauce at this stage. If it is too sweet or too tart, adjust by adding a small amount of water. Once satisfied with the flavor and thickness, proceed to the final step.
Add the Pork and Serve: Toss the crispy pork into the sauce, ensuring each piece is evenly coated. Serve immediately for the best texture and flavor.