Place the cooked rice in the refrigerator to chill until ready to use.
Place butter in a large skillet or wok. Add onion, carrots and peas. Cook for 2 minutes. Then stir in garlic. Push to one side and add the eggs to the skillet. Scramble and then stir together. Gently stir in cooked rice.
Add soy sauce and oyster sauce and toss to coat. Salt and pepper to taste. Serve while warm.