Heat 2 tablespoons of vegetable oil in a large pan over medium heat. Add ½ cup diced onion and ½ cup diced bell pepper, cooking for about 5 minutes until softened.

Add 2 cups of cooked short-grain Japanese rice, along with ½ cup frozen peas, 2 tablespoons of ketchup, and 2 tablespoons of demi-glace or stock to the pan. Mix thoroughly and cook for about 3-4 minutes.

In a medium bowl, crack 4 large eggs and add 2 tablespoons of milk. Whisk together until smooth and season with a pinch of salt.

In a clean non-stick pan, heat a small amount of oil over medium heat. Pour in the egg mixture and swirl to cover the pan. Cook for about 3-4 minutes until edges set but center remains runny.

Spoon the rice filling into the center of the omelet. Fold the sides of the omelet over the filling. Slide the Omurice onto a plate.

Serve hot, garnished with additional ketchup or sauces if desired.