Stir golden mushroom soup, water, onion, Worcestershire sauce, and onion soup mix together in a slow cooker; add beef and stir to coat.
Cook on Low for 6 hours.
Stir cream cheese and sour cream into the beef mixture.
Melt butter in a skillet over medium heat. Cook and stir mushrooms in melted butter until tender, 3 to 5 minutes; add to beef mixture.
Bring a large pot of lightly salted water to a boil. Cook egg noodles in the boiling water, stirring occasionally until cooked through but firm to the bite, about 5 minutes. Drain. Ladle beef mixture over noodles to serve.