In a large skillet, heat 2 tablespoons of butter or cooking oil over medium heat. Add finely chopped onion and sauté for 2-3 minutes until soft and translucent.

Incorporate diced chicken, shrimp, or tofu, stirring for about 2 minutes until cooked through, then add mixed vegetables.

Add day-old cooked rice, breaking up any clumps, and stir in ketchup and soy sauce. Cook for another 2-3 minutes until the rice is evenly coated, then form a mound on a plate.

In a mixing bowl, whisk together 3 large eggs, a splash of milk, salt, and pepper until well combined.

Heat a non-stick pan over medium-low heat and melt a bit of butter. Pour the egg mixture into the pan, swirling gently to create a thin layer. Cook slowly for 1-2 minutes until the edges start to set.

Carefully slide the cooked omelet over the mound of fried rice on your plate. Drizzle ketchup in creative patterns on top.

Sprinkle freshly chopped parsley over your Omurice for added color and freshness. Serve warm.