01 -
In a large skillet set over medium heat, cook the ground beef with the chopped onion for 5 to 7 minutes until the beef is thoroughly browned and no pink remains. Drain excess fat from the pan.
02 -
Wash and thinly slice the potatoes evenly to about 1/8 inch thickness to ensure uniform cooking.
03 -
Arrange half of the sliced potatoes in an even layer at the bottom of the crockpot. Add half the cooked beef and onion mixture over the potatoes, then sprinkle with a portion of the shredded cheddar cheese. Repeat the layers with the remaining potatoes, beef mixture, and some of the cheese.
04 -
In a medium bowl, whisk together the cream of mushroom soup, milk, garlic powder, salt, and black pepper until smooth. Pour the sauce mixture evenly over the layered ingredients in the crockpot.
05 -
Cover and cook on low heat for 6 to 8 hours or until the potatoes are tender and the cheese is melted and bubbly.
06 -
Sprinkle the remaining shredded cheddar cheese evenly over the casserole about 15 minutes before serving. Cover and allow the cheese to melt fully. If desired, garnish with fresh parsley or chopped chives just before serving.