Ham and au Gratin Potatoes

6 large potatoes, peeled and sliced
1 medium onion, coarsely chopped
1 1/2 cup ham, cooked, cubed
1 cup American cheese, shredded
1 can cream of mushroom soup
1/2 cup milk
2 dashes thyme

In crockpot, layer half each of the potatoes, onion, ham and cheese; repeat layers.

In small bowl, combine soup, milk and thyme; pour over top of ingredients in crockpot. Cover; cook on HIGH for 1 hour.

Reduce to LOW setting; cook for 6 to 8 hours or until potatoes are tender.