Loaded Potato & Meatloaf Casserole

Preheat oven to 375°F (190°C). In a bowl, combine ground beef, onion, garlic, breadcrumbs, milk, egg, Worcestershire sauce, salt, and pepper. Press the mixture into the bottom of a greased baking dish. Spread ketchup over the top of the meatloaf. Bake for 25 minutes. Meanwhile, boil the sliced potatoes until tender, about 15 minutes. Drain and mash with sour cream, milk, and butter. Season with salt and pepper. Spread the mashed potatoes over the partially cooked meatloaf. Sprinkle with cheddar cheese and green onions. Return to the oven and bake for another 20 minutes, or until the cheese is melted and bubbly. Let rest for 10 minutes before serving.