Preheat the oven to 375°F (190°C).
Heat olive oil in a large skillet over medium heat.
Add the chopped onion and minced garlic to the skillet and sauté until softened, about 3-4 minutes.
Add the ground beef to the skillet, breaking it apart with a spatula, and cook until browned and no longer pink, about 6-8 minutes.
Season the beef mixture with salt, black pepper, dried thyme, and paprika. Stir well to combine.
Remove the skillet from heat and set aside.
In a large mixing bowl, combine the beef broth and sour cream until smooth.
Lightly grease a 9×13 inch baking dish.
Arrange half of the sliced potatoes in an even layer on the bottom of the baking dish.
Spread half of the cooked ground beef mixture evenly over the potatoes.
Pour half of the sour cream and beef broth mixture over the beef layer.
Repeat layering with the remaining sliced potatoes, ground beef mixture, and sour cream mixture.
Cover the baking dish tightly with aluminum foil.
Bake in the preheated oven for 45 minutes.
Remove the foil and sprinkle the shredded cheddar cheese evenly over the top.
Return the casserole to the oven and bake uncovered for an additional 15 minutes, or until the cheese is melted and bubbly and the potatoes are tender when pierced with a fork.
Remove from the oven and let the casserole rest for 5 minutes before serving.