Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat.

Add the beaten eggs to the skillet and scramble until just cooked. Remove the scrambled eggs from the skillet and set aside.

In the same skillet, add the remaining tablespoon of vegetable oil. Add the diced onion and cook for 2-3 minutes until softened.

Add the minced garlic to the skillet and cook for an additional 1 minute until fragrant.

Stir in the mixed vegetables and cook for 3-4 minutes until tender-crisp.

Add the cooked rice to the skillet, breaking up any clumps with a spatula or wooden spoon. Stir-fry the rice with the vegetables for 2-3 minutes until heated through.

Return the scrambled eggs to the skillet and stir to combine with the rice and vegetables.

Drizzle the soy sauce and oyster sauce (if using) over the rice mixture. Stir well to evenly distribute the sauces.

Season the fried rice with salt and pepper to taste. Adjust the seasoning as needed.

Continue to cook the fried rice for an additional 2-3 minutes, stirring occasionally, until everything is well combined and heated through.

Remove the skillet from the heat and transfer the fried rice to a serving dish.

Garnish the fried rice with chopped green onions (if using) for a pop of color and freshness.