Prepare the rice:
Use cold, day-old rice for best texture. Freshly cooked rice tends to be too moist and may clump. If using fresh rice, spread it out on a tray and chill in the fridge for at least 30 minutes to dry it out slightly.
Brown the beef:
Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat. Add the ground beef and break it up with a spatula. Cook until browned and cooked through, about 6–8 minutes. Drain excess grease if needed.
Sauté aromatics:
Add chopped onion to the beef and sauté for 2–3 minutes, until softened. Stir in the minced garlic and cook for another 30 seconds until fragrant.
Add vegetables:
Toss in the mixed vegetables and stir-fry for 3–4 minutes until tender-crisp and heated through. If using frozen veggies, thaw slightly before adding.
Add rice:
Add the cold rice to the skillet, breaking apart any clumps with a spatula. Stir well to combine with the meat and veggies.
Season:
Pour in the soy sauce, oyster sauce, and sesame oil. Toss the rice mixture until evenly coated and heated through. Taste and adjust salt and pepper as needed.
Serve:
Serve hot, garnished with chopped green onions or cilantro for a fresh finish. Add a fried egg on top for extra richness, if desired.
