Preheat the Oven: Set your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish.
Cook the Ground Beef: In a large skillet over medium heat, cook the ground beef until browned and fully cooked, breaking it up with a spatula as it cooks. Add the chopped onion and minced garlic, cooking until the onion becomes translucent, about 5 minutes. Drain any excess grease.
Prepare the Creamy Sauce: In a small saucepan, melt the butter over medium heat until fully liquefied. Whisk in the flour and cook for 1 minute, stirring constantly to prevent lumps. Gradually add the beef broth and milk, whisking until smooth. Cook the mixture, stirring frequently, until it thickens, about 3-4 minutes. Season with salt, pepper, and paprika.
Assemble the Casserole: In your prepared baking dish, layer half of the sliced potatoes on the bottom. Evenly spread half of the cooked ground beef mixture over the layer of potatoes, ensuring full coverage. Pour half of the creamy sauce over the beef, followed by a sprinkle of shredded cheese. Repeat with the remaining potatoes, beef mixture, and sauce, finishing with a final layer of cheese on top.
Bake the Casserole: Cover the dish with aluminum foil and bake for 40 minutes. Your free plan comes with 100 prompts per month. Your next refill is in 25 days. To get more prompts, upgrade to Pro.
Garnish and Serve: Remove the casserole from the oven and let it sit for a few minutes to cool slightly. Sprinkle with fresh parsley if desired. Serve hot and enjoy!