Spray the bottom and sides of a 6 quart slow cooker with cooking spray.

Peel and slice the potatoes and dice the ham. Grate the cheese.

In the bottom of the slow cooker, layer half of the potato slices, half the garlic powder and pepper, half the onion, half the ham, and a third of the cheese. Repeat layers.

Mix the soup and milk together and spread evenly over the top. Place the lid on the slow cooker.

Cook on LOW for 6-8 hours, or until the potatoes are tender.

Sprinkle the last third of the shredded cheese over the top of the potatoes. Cover for about 5 minutes, or until the cheese melts.