Prepare the Bread: Cut your stale bread into small cubes (about 1cm). Place them in a large bowl.
Soak: Pour the warm milk over the bread cubes. Cover the bowl and let it sit for at least 20 minutes. The bread should soak up all the liquid but not become a total mush.
Sauté: In a small pan, melt the butter and sauté the onions and parsley until the onions are translucent. Let it cool slightly, then add it to the bread.
Mix: Add the eggs, nutmeg, salt, and pepper to the bread. Use your hands to mix it gently. You want a cohesive dough, but you still want to see some structure of the bread cubes. If it feels too sticky, add a spoon of breadcrumbs.
The Rest: Let the dough rest for another 10-15 minutes. This is crucial for the stability of the dumpling!
Shape: With wet hands (this prevents sticking), roll the dough into balls about the size of a tennis ball. Make sure the surface is smooth with no deep cracks.
Simmer: Bring a large pot of salted water to a boil, then turn it down to a very low simmer. The water should not be bubbling hard!
The Float: Drop the dumplings in. They will sink at first. Let them simmer (not boil!) for about 20 minutes. Once they float to the top and stay there, they are done.