1. Peel potatoes and cook in salted boiling water until tender.
2. Drain potatoes and cool or refrigerate overnight or for 30 minutes.
3. Mash potatoes or use a ricer.
4.. Cut bread into 1/2-inch squares and fry in melted butter until coated. Place in oven at 350 degrees until golden brown and crunchy.
5. Place potatoes in a bowl add onions, egg, flour, cornstarch, salt and nutmeg. mix well using hands or a wooden spoon. If to sticky add a little at a time.
6. Form balls using 1/4 cup for each ball.
7. Insert a bread cube into the middle of each ball. Roll dumpling between palms to enclose bread.
8. Bring a large pot of salted water to a rolling boil. Cooking in batches drop each dumpling into the boiling water. Cook 10-15 minutes or until dumpling raises to the top of the water.
9. Use a slotted spoon, transfer each dumpling to a bowl. Cover with a warm damp kitchen towel while the remaining dumplings are cooked.
10. You should place no more than 4-5 dumpling in the pot at one time to keep them from sticking together.