Break up the rice: Separate any large clumps of the chilled rice with your hands before cooking.
Sauté the garlic: Heat the oil in a wok or large skillet over medium-high heat. Add the garlic and stir-fry until fragrant and lightly golden, about 20 seconds.
Cook the protein: Add the pork (or your preferred protein) and stir-fry until almost cooked through.
Scramble the eggs: Push everything to one side of the wok. Crack in the eggs, scramble until just set, then mix with the pork.
Add the sauces: Pour the oyster sauce, light soy sauce, dark soy sauce, and sugar around the edges of the wok. Toss until the pork is evenly coated.
Stir-fry the vegetables: Add the carrot and onion and cook for 1-2 minutes, depending on how tender you like them.
Add the rice: Stir in the leftover rice and break up any remaining clumps with your spatula. Stir-fry for 2-3 minutes, letting the rice sit briefly between stirs to lightly toast.
Finish and serve: Stir in the green onions, season with white pepper if using, and serve immediately.