Au Gratin Potatoes And Ham

3 C potatoes -- peeled and sliced
1/2 Med onion -- coarsely chopped
3/4 C ham -- cooked, cubed
1/2 C American cheese -- shredded
1/2 Can cream of mushroom soup
1/4 C milk
1 Dash thyme

In slow cooker, layer half each of the potatoes, onion, ham and cheese; repeat layers. In small bowl, combine soup, milk and thyme; pour over top. Cover; cook on high setting for 1 hour. Reduce to low setting; cook for 6 to 8 hours or until potatoes are tender.