Cook potatoes in boiling water until tender; drain and cool. Refrigerate overnight.
The next day, peel and grate potatoes. Add 1 cup flour, egg, salt, pepper and onion; mix until smooth. Add additional flour gradually to form dumpling mixture that will hold together. Form into balls the size of an egg. Insert 2 to 3 croutons into each dumpling, then again form into a ball. When ready to cook, drop dumplings into gently boiling salted water and cook 8 to 10 minutes. Dumplings are done when they turn and float to top and are no longer gummy inside.Makes 4 Source: