Preheat the oven to 400 degrees. Prick the potatoes several times with a fork, place them on a baking sheet, and bake for 45 minutes until tender. Let them cool slightly, then cut each potato into bite-size chunks.

While the potatoes bake, heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 minutes until softened.

Add the ground beef, garlic, salt, and black pepper to the skillet. Cook for 8 minutes, breaking up the meat, until the beef is browned and no longer pink. Drain any excess fat.

Reduce the oven temperature to 375 degrees. Spread the potato chunks in a greased 9x13 baking dish. Spoon the beef mixture evenly over the potatoes.

Sprinkle the shredded cheddar cheese over the top. Bake for 15 minutes until the cheese is fully melted and bubbly.

Remove the dish from the oven. Top with crumbled bacon, dollops of sour cream, and sliced green onions before serving.