Preheat oven to 375°F (190°C).
- In a skillet, cook ground beef with onion and garlic until browned. Drain excess fat. Season with salt, pepper, paprika, and thyme if using.
- Grease a 9×13-inch baking dish. Layer potato slices evenly on the bottom.
- Spread cooked beef mixture over potatoes.
- Add a layer of carrots and green beans or mixed vegetables.
- Spread cream of mushroom soup evenly over the top.
- Cover with foil and bake for 45–50 minutes, until vegetables are tender.
- Remove foil, sprinkle cheddar cheese over the casserole, and bake uncovered for 10–15 minutes until melted and bubbly.
- Let rest 5 minutes before serving.