Preheat oven to 400°F (200°C).
In a 9x13 inch baking dish, toss the cubed potatoes with 2 tablespoons of olive oil, 0.5 teaspoon salt, and 0.25 teaspoon pepper.
Roast the potatoes for 30 minutes, stirring once halfway through, until edges are golden brown and centers are tender.
While potatoes roast, heat the remaining 1 tablespoon of olive oil in a large skillet over medium-high heat.
Add the ground beef and onion to the skillet; cook until the beef is fully browned and the onions are translucent.
Stir in the minced garlic, smoked paprika, dried oregano, and the remaining salt and pepper; cook for 2 minutes then drain excess fat from the skillet.
Remove the baking dish from the oven and spread the cooked beef mixture evenly over the roasted potatoes.
Sprinkle the shredded cheddar cheese over the beef layer.
Return the dish to the oven and bake for 8 to 10 minutes until the cheese is completely melted and slightly bubbling.
Remove from oven and garnish with fresh parsley before serving.