Preheat your oven to 375°F and lightly coat a 9x13 inch baking dish with cooking spray.

In a large skillet, cook the ground beef with the diced onion and minced garlic until the beef is browned. Drain the excess fat and season with salt and pepper.

Arrange a layer of sliced potatoes at the bottom of the prepared baking dish. Spread half of the cooked beef mixture over the potatoes.

In a bowl, whisk together the cream of mushroom soup, cream of chicken soup, evaporated milk, and regular milk until well combined. Pour half of this soup mixture over the beef and potatoes. Sprinkle half of the shredded cheese on top.

Repeat the layers with the remaining potatoes, beef mixture, soup mixture, and finish with the remaining cheese.

Cover the dish with aluminum foil, tenting it slightly to prevent the cheese from sticking.

Bake in the preheated oven for 1 hour. After an hour, remove the foil and continue baking for another 30 minutes until the top is golden and bubbly.

Let the casserole stand for 10 minutes before slicing and serving.