Preheat your oven to 375°F (190°C). Grease a 9x13 inch baking dish with butter or cooking spray. In a medium bowl, combine the thinly sliced potatoes, half of the sliced onion, and season with salt and pepper.

In a saucepan over medium heat, melt the butter. Add the remaining onion and garlic, and sauté until softened. Sprinkle in the flour and whisk constantly for 1 minute. Gradually add the beef broth and heavy cream, whisking until smooth. Stir in half of the cheddar cheese until melted and sauce thickens.

Layer the potato mixture in the prepared baking dish. Pour half of the cream sauce over the potatoes. Arrange the beef chops on top of the potatoes, then pour the remaining sauce over everything. Sprinkle with paprika and dried thyme.

Cover the dish with foil and bake for 45 minutes. Remove the foil, sprinkle with remaining cheese, and bake uncovered for another 15-20 minutes until the beef is cooked through and potatoes are tender.

Let the casserole rest for 5-10 minutes before serving. Garnish with fresh parsley and serve hot.