Wash potatoes well with cool water, removing any debris. Leave skins on and quarter and add to a pot of hot water over high heat prepared to boil. Cook until the potatoes are tender (about 15 minutes).
Meanwhile, in a large frying pan, add ground beef with a few drops of water, onion and mushrooms to sauté. Cook until the meat is browned. Drain any grease.
Add 1 can cream of mushroom soup to the meat mixture. Heat on low until warmed through.
Finish the mashed potatoes by removing them from the heat when they are tender. Drain water and transfer them to an electric mixer.Add cream cheese, sour cream, butter and milk. Beat until whipped.
Serve mashed potatoes with stroganoff mixture on top. Garnish with chopped fresh parsley.