In a bowl, mix the pork cubes with soy sauce, Shaoxing wine, and the egg. Let it marinate for 10 minutes.

Coat each piece of pork generously in cornstarch, shaking off any excess powder.

Heat oil in a deep pan or wok to 350°F (175°C). Fry the pork in batches for 3-4 minutes until pale golden and cooked through. Remove and drain.

Increase oil heat to 375°F (190°C). Return the pork to the oil for a quick second fry (about 1 minute) until golden brown and very crispy. Set aside.

In a separate wok or pan, stir-fry the onion and bell peppers for 2 minutes until slightly softened but still crisp.

Add the ketchup, rice vinegar, sugar, and pineapple chunks to the pan. Simmer until the sauce bubbles and thickens slightly.

Toss the crispy pork into the sauce, stirring quickly to coat every piece evenly. Serve immediately with steamed rice.