Heat the vegetable oil in a large skillet or wok over medium-high heat.

Add the onion and garlic, and sauté for 2-3 minutes, until the vegetables are tender.

Add the diced ham to the skillet and cook for another 2-3 minutes, stirring occasionally, until the ham is browned.

Push the ham and vegetables to one side of the skillet and add the beaten eggs to the other side. Scramble the eggs until cooked through, then mix them with the ham and vegetables.

Add the chilled rice to the skillet, breaking up any clumps with a fork.

Add the frozen peas and carrots, and stir to combine.

Drizzle the soy sauce over the top of the rice, and stir well to evenly distribute.

Cook for another 5-7 minutes, stirring occasionally, until the rice is heated through and the vegetables are tender.

Season with salt and pepper to taste, and garnish with sliced green onions, if desired.