01 -
Slice the potatoes into ⅛-inch thick slices and place them in water to prevent oxidation.
02 -
Preheat the oven to 350°F. Lightly spray a 9x13-inch baking dish with nonstick cooking spray and set aside.
03 -
Cook ground beef, diced onions, and garlic in a large saucepan over medium-high heat until browned, breaking up the meat as it cooks. Drain excess oil.
04 -
Mix the cream of mushroom soup, half and half, onion powder, kosher salt, and pepper in a medium bowl until smooth.
05 -
Drain the potato slices. Layer ⅓ of the potatoes in the baking dish, followed by ⅓ of the ground beef mixture, ¾ cup of shredded cheese, and ⅓ of the soup mixture. Repeat this process for a second layer.
06 -
Add a final layer of potatoes and ground beef, pour the remaining soup mixture on top, and sprinkle with 1½ cups of shredded cheese.
07 -
Cover the dish tightly with aluminum foil and bake for 1 hour and 10 minutes. Remove the foil and bake for an additional 20 minutes. Allow to rest for 15 minutes before serving.