Preheat the oven to 375°F (190°C).
In a mixing bowl, combine ground beef, chopped onion, egg, breadcrumbs, ketchup, soy sauce, oregano, salt, and white pepper. Mix well.
Spread the meat mixture evenly in the bottom of a greased casserole dish.
Bake in the preheated oven for about 25-30 minutes or until cooked through.
In a separate bowl, add boiled potatoes, shredded cheddar cheese, butter, heavy whipping cream, sour cream, salt, white pepper, chopped green onion, and chopped bacon. Mix until well combined.
Once the meatloaf base is cooked, spread the mashed potato mixture evenly over the meatloaf.
Sprinkle shredded cheddar cheese and chopped bacon on top.
Place the casserole back in the oven and bake for an additional 15-20 minutes, or until the cheese is melted and bubbly.
Once done, let it cool slightly before serving.
Garnish with additional green onion, if desired.