Preheat your oven to 375°F (190°C).

In a large bowl, combine ground beef, breadcrumbs, egg, and milk. Add garlic powder, onion powder, salt, and pepper.

Press the meat mixture evenly into a 9x13-inch baking dish and bake uncovered for 20 minutes.

While the meatloaf bakes, boil a large pot of water and add diced russet potatoes. Cook for about 15 minutes until fork-tender.

Drain the potatoes and return them to the pot. Add milk, butter, and a pinch of salt and pepper, then mash until creamy.

Spread the mashed potatoes evenly over the meatloaf layer after 20 minutes of baking.

Sprinkle shredded cheddar cheese, crumbled turkey bacon, and sliced green onions on top.

Return the casserole to the oven and bake for an additional 15 minutes until the cheese is melted.

Let the casserole sit for a few minutes before slicing and serving.