Boil the spaghetti and drain. In the meantime, defrost the creamed spinach in a saucepan over medium heat while stirring. Caution can start quickly! Press the feta into small pieces with a fork and add to the spinach together with the sour cream, heat for 5 minutes while stirring. Put the spaghetti on a plate and cover with the spinach sauce. If you like, you can also dice a slice of cooked ham and sprinkle it on top.