This soothing soup with Parmesan dumplings (passatelli) was a Sunday staple at Fabio Trabocchi's home. He would compete with his father to see who made the best chicken stock.Plus: More Soup Recipes and Tips
In a bowl, beat the eggs with the yolk. Stir in the cheese, bread crumbs, lemon zest, nutmeg and butter. Cover the dough; chill until firm. Bring the dough to room temperature before cooking.
In a large saucepan, bring the stock to a boil. Season with salt and reduce the heat so the stock simmers.
Press one-third of the passatelli dough at a time through a ricer, cutting it in 1/2-inch lengths over the soup. Simmer until all of the passatelli surface, about 1 minute. Serve the soup in wide bowls.
The passatelli dough can be refrigerated overnight.