Preheat Oven: Set your oven to 375°F (190°C) and lightly grease a 9x13-inch casserole dish.
Cook the Beef Mixture: In a large skillet, cook ground beef over medium-high heat until browned and no longer pink. Drain excess fat if needed. Stir in diced onion, minced garlic, garlic powder, onion powder, salt, and pepper. Cook for 2–3 minutes until fragrant.
Mix with Soups: Add the cream of mushroom soup and cheddar cheese soup to the beef mixture. Stir well until everything is combined into a creamy filling.
Assemble the Casserole: Spread the beef and soup mixture evenly into the prepared casserole dish. Top with a layer of frozen French fries.
Bake: Place the dish in the oven and bake for 30–35 minutes, or until the fries are golden brown and crispy.
Add Cheese: Remove the casserole, sprinkle shredded cheddar cheese over the top, and bake for an additional 5–7 minutes until melted.
Make Burger Sauce: While the casserole bakes, whisk together mayonnaise, ketchup, mustard, pickle juice, dried onion flakes, and black pepper in a small bowl. Refrigerate until ready to serve.
Serve: Once the casserole is done, drizzle with burger sauce or serve on the side.