sanya's ham and noodle casserole

1 onion
2 cans cream of mushrooom
1 c. milk
chop and cook onion. add soup and milk. remove from heat and add:
2 c. sour cream

8 oz. package of noodles-- cooked

4 c. diced ham

layer 1/2 noodles, 1/2 ham, 1/2 sauce in 9x13 pan. top with cheese. cook at 350 until done.