1. Combine sherry, pepper, 1 tablespoon of the soy sauce, and ½ teaspoon of the sugar in a medium bowl. Add pork and gently toss until well coated. Let marinate in the refrigerator.

2. In a saucepan, bring the stock to a boil and add rice. Cover with a lid and let simmer for 20 to 30 minutes. Using a fork, fluff the grains and serve on 4 plates.

3. Meanwhile, stir together pineapple juice, ketchup, vinegar, remaining tablespoon of soy sauce, and remaining teaspoon of sugar in a small bowl until well combined. Set aside.

4. Heat 1 tablespoon of the oil in a large, nonstick skillet over medium-high heat until hot but not smoking. Add onion and cook, stirring occasionally, until browned but still a little crisp, about 2 minutes. Transfer to a bowl.

5. Heat another tablespoon oil in the same skillet over medium-high heat until hot but not smoking. Add peppers and cook, stirring occasionally, until browned but still a little crisp, about 3 minutes. Add to onions.

6. Heat remaining tablespoon oil in the same skillet over medium-high heat, until hot but not smoking. Add the pork cubes, arranging in a single layer. Cook, undisturbed, until a golden brown crust forms on the bottom, about 1½ minutes. Turn the cubes over and cook until a golden brown crust forms on the other side, about 1½ minutes. Return the onion and peppers to the pan and toss to combine. Add pineapples and pineapple juice mixture and cook, stirring, until sauce evenly coats everything and thickens slightly, about 2 minutes. Serve immediately over rice.