Prepare Ingredients: Gather all your ingredients for the Omurice, including cooked rice, diced chicken, chopped onions, minced carrots, peas, eggs, and ketchup.

Cook Filling: Heat 1 tablespoon of cooking oil in a large skillet over medium heat. Add chopped onions and sauté until translucent, about 3-4 minutes, then add diced chicken and cook until no longer pink, about 5 minutes. Add carrots and peas and sauté for another 2-3 minutes until tender.

Mix Rice: Stir in cooked rice and drizzle in ketchup, mixing thoroughly. Season with salt and pepper to taste and cook on low heat for about 5 minutes.

Whip Omelet: Beat the eggs with a pinch of salt until frothy. Heat 1 tablespoon of cooking oil in a non-stick skillet over medium-low heat and pour half of the beaten eggs. Cook until edges set, about 2-3 minutes.

Assemble Omurice: Spoon half of the fried rice filling onto one side of the omelet, fold the other half over the rice. Repeat with remaining ingredients.

Serve: Slide the assembled Omurice onto serving plates, drizzle with extra ketchup or soy sauce if desired.