Heat oil in a large skillet over medium-high heat. Add onion and carrots and cook until vegetables are tender, about 5 minutes.
Add peas and cooked rice to the skillet and stir to combine.
Stir in soy sauce and cook until heated through, about 3 minutes.
Push the rice mixture to one side of the skillet. Pour the egg onto the empty side of the skillet. Cook, stirring occasionally until egg is scrambled and cooked through.
Stir the egg into the rice mixture and cook for an additional minute.