Preheat your oven to 350°F (175°C). Cook the ground beef and diced onion in a skillet with ½ teaspoon salt and ¼ teaspoon pepper until the beef is browned and fully cooked. Drain any excess grease and set aside.

In a mixing bowl, whisk together the cream of chicken soup, evaporated milk, regular milk, 1 teaspoon salt, ¼ teaspoon pepper, and onion powder until smooth.

Lightly grease a 9×13-inch baking dish. Arrange one-third of the sliced potatoes evenly in the bottom of the dish, followed by one-third of the cooked ground beef mixture. Sprinkle 1 cup of shredded cheese over the top. Lightly season with a pinch of salt and pepper. Repeat this layering process two more times, creating a total of three layers.

Evenly pour the milk mixture over the entire casserole. Cover the dish tightly with aluminum foil and bake for 1 hour.

Check the tenderness of the potatoes by inserting a fork. If fully cooked, remove the foil and sprinkle the remaining cheese evenly across the top. Return the casserole to the oven, uncovered, and bake for an additional 5 minutes, or until the cheese is melted.

Remove from the oven and let the casserole rest for 15 minutes to allow the layers to set before serving.

Enjoy warm as a satisfying meal for any occasion.