Preheat your oven to 375°F. Grease a 9x13-inch baking dish—don’t skip this unless you want to chisel out your dinner later.
In a large skillet over medium heat, warm the olive oil and toss in the diced onion. Cook until softened, about 5 minutes. Stir in garlic, cook for another 30 seconds.
Add the ground beef to the skillet, breaking it up as it browns. Cook until no longer pink, then drain the fat if there’s more than you’d like.
Transfer the beef mixture to a large mixing bowl. Add salt, pepper, Worcestershire sauce, ketchup, eggs, and half the shredded cheese. Mix until combined, but don’t overdo it—nobody likes rubbery meatloaf.
Spread the meat mixture evenly in the prepared baking dish. Spoon mashed potatoes across the top and smooth into a soft layer—think frosting, but savory.
Sprinkle the remaining cheddar cheese over the mashed potatoes. Bake uncovered for 25 to 30 minutes, or until the cheese is melted and bubbly.
Top with chopped green onions if you’re feeling fancy, then serve hot. Leftovers hold up like champs.