In a skillet, cook the ground beef over medium heat until browned. Drain excess fat.
Add the chopped onion and minced garlic to the skillet. Cook until the onion is translucent.
In a mixing bowl, combine the cream of mushroom soup and milk. Stir in salt and pepper to taste.
In a baking dish, layer half of the sliced potatoes, followed by half of the ground beef mixture. Pour half of the soup mixture over the beef. Repeat the layers.
Sprinkle the shredded cheddar cheese on top.
Cover the baking dish with aluminum foil and bake for 45 minutes. Remove the foil and bake for an additional 15 minutes, or until the potatoes are tender and the cheese is bubbly and golden.
Let the casserole cool for a few minutes before serving.
Notes:
This casserole is perfect for a cozy family dinner. You can also add some veggies like peas or carrots for extra nutrition.