Cheesy Salloped Potatoes & Ham

5 cups peeled russet potatoes, sliced thinly
1/2 - 1 cup chopped onion
1 can cream of mushroom soup
3/4 cup. sour cream
1-1/2 cup shredded cheddar cheese
1 lb. chopped ham

Peel and wash the potatoes. Slice them as thin as you can get them. If you slice them thick, they will take much longer to bake and nothing is worse than a crunchy potato. Next, mix together the soup, cheese, and sour cream. Chop the onion finely. Mix together well. Add in the potatoes and mix. Pour into a well-greased casserole dish. Bake, covered, in a 350 preheated oven for one hour. In the meantime, chop your ham.Remove dish from oven and add the ham, mixing well. Potatoes will start to really stick, so make sure to scrape them from the sides at this time as well. Cover and put back in the oven for 30-60 more minutes, or until potatoes are soft. Remove from the oven.