Preheat oven to 350 degrees. Spray a 9 x 13 inch baking dish with non-stick cooking spray.
Chop potatoes into large cubes and boil in a pot of water on the stove top until softened (about 10-15 minutes).
Mix cooked potatoes with ham and put in a 9 x 13 dish.
In a separate bowl, beat together soup, salad dressing mix, and cream cheese. Stir soup mixture into potatoes and ham and top with shredded Parmesan cheese.
Cover pan with aluminum foil and bake for 30-35 minutes.
Notes
You could also use a can of cream of chicken soup instead of cream of potato soup.