In a skillet, cook the ground beef over medium heat until browned. Drain any excess fat.
Add the chopped onion and minced garlic to the skillet. Cook until the onion is translucent.
In a mixing bowl, combine the milk, salt, and pepper.
Layer half of the sliced potatoes in a greased baking dish. Top with half of the ground beef mixture and half of the shredded cheese. Repeat the layers.
Pour the milk mixture over the top of the casserole. Dot with butter.
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 top is golden brown.
Let the casserole cool for a few minutes before serving.
Notes:
This casserole is perfect for a cozy family dinner.