Preheat your oven to 375°F (190°C) and grease a 9x13-inch baking dish using olive oil.

In a large skillet, heat a tablespoon of olive oil over medium heat. Add chopped onions and minced garlic, sautéing until softened and fragrant, about 3-4 minutes.

Increase the heat slightly and add the ground beef to the skillet. Cook until browned and fully cooked, breaking it apart, about 5-7 minutes. Season with salt and pepper.

Layer the sliced potatoes evenly in the greased baking dish, creating a solid base.

Once the ground beef is cooked, pour and spread the beef mixture over the layered potatoes. Sprinkle the cheddar cheese on top.

Cover the baking dish tightly with aluminum foil and bake for 30 minutes.

After 30 minutes, remove the foil and bake for an additional 15-20 minutes until the potatoes are tender and the cheese is melted and bubbly.

Let the casserole cool slightly, then garnish with freshly chopped parsley before serving.