Preheat the oven to 300 degrees F (150 degrees C).

In a large mixing bowl, combine the stew meat, cream of mushroom soup, and dry onion soup mix.

Mix well until the meat is evenly coated with the soup mixture.

Transfer the mixture to a casserole dish, spreading it out evenly.

Cover the casserole dish with a lid or aluminum foil.

Place the covered casserole dish in the preheated oven and bake for 3 hours, or until the beef is tender and cooked through.

Once cooked, remove the casserole from the oven and let it rest for a few minutes.

Serve the Creamy Oven Beef Stroganoff hot over cooked egg noodles or rice.

Garnish with chopped parsley or a dollop of sour cream if desired.