Heat the Oil:
In a large skillet or wok, heat the vegetable oil over medium-high heat.
Cook the Aromatics:
Add the minced garlic and diced onion to the skillet. Stir-fry for 1-2 minutes until fragrant and the onions are slightly softened.
Add the Vegetables and Protein:
Toss in the mixed vegetables and your choice of cooked protein. Stir-fry for 3-4 minutes until the vegetables are tender.
Scramble the Eggs:
Push the vegetables and protein to one side of the skillet. Pour the beaten eggs onto the empty side and scramble until just set. Mix them into the vegetables.
Add the Rice:
Add the cooked rice to the skillet. Break up any clumps with your spatula and mix well with the other ingredients.
Season the Fried Rice:
Pour in the soy sauce, oyster sauce, and sesame oil (if using). Sprinkle with black pepper. Stir-fry everything for 3-4 minutes until the rice is heated through and evenly coated with the sauce.
Garnish and Serve:
Remove from heat and sprinkle with chopped green onions. Serve hot and enjoy your quick, delicious fried rice!