Preheat the oven to 375°F (190°C).
Peel and dice the potatoes into small, even cubes. Chop the onion and mince the garlic cloves.
Heat olive oil in a large skillet over medium heat. Add chopped onion and garlic; sauté until softened and fragrant.
Add ground beef to the skillet. Season with salt, black pepper, dried thyme, and paprika. Cook, breaking up meat, until browned and fully cooked.
Pour in beef broth and stir. Let the mixture simmer for a few minutes, then remove from heat.
In a large mixing bowl, combine diced potatoes with the beef mixture. Fold in sour cream and half of the shredded cheddar cheese until well mixed.
Transfer the mixture to a baking dish and spread evenly. Sprinkle remaining cheddar cheese on top.
Cover the dish tightly with aluminum foil and bake for 30 minutes.
Remove foil and bake uncovered for an additional 10 to 15 minutes until cheese is melted and bubbling.
Allow the casserole to rest for 10 minutes before serving for best texture.