If you accidentally put in too much liquid to the pureed soup, an easy way to thicken the soup is to add more cooked white beans into it. Cooked potato or other cooked root vegetables work also. Puree it again with a hand mixer. u003cbr/u003eYou can also thicken the soup with 1-2 tbsp of cornstarch mixed in cold water. Bring then to a boil for 2 minutes.