Prepare beef and potatoes:
Brown the ground beef in a skillet over medium heat until fully cooked. Drain any excess fat and set aside. Peel the potatoes and slice them thinly. Set aside.

Mix the sauce:
In a mixing bowl, whisk together the cream of mushroom soup, milk, salt, and pepper until well combined. Set aside.

Layer and assemble:
Spray the inside of the crock pot with non-stick cooking spray. Begin layering by placing a layer of potato slices evenly at the bottom, followed by a layer of browned ground beef. Pour a portion of the soup mixture over the beef, then sprinkle with shredded cheese. Repeat these layers until all ingredients are used, finishing with a generous layer of shredded cheese on top.

Cook and finish:
Cover the crock pot with the lid and cook on high for 3 to 4 hours, or until the potatoes are tender when pierced with a fork. Once done, turn off the crock pot and let the casserole sit uncovered for about 10 minutes to thicken slightly.

Serve:
Cut the casserole into portions and serve warm alongside your favorite vegetable or salad.