Bring a large pot of salted water to a boil. Add potatoes and cook until tender, about 15 minutes. Drain and mash.

In a medium bowl combine 2 cups mashed potatoes with flour and egg. Using about 1/4 to 1/2 cup of mixture each, shape into dumplings. Press a crouton into the center of each and seal dough around it.

Drop dumplings into simmering soup or broth, cover and cook 20 minutes. Do not remove lid while dumplings are cooking.