For the passatelli, in a large mixing bowl, lightly beat eggs. Stir in the bread crumbs, 1 cup freshly grated Parmigiano-Reggiano or Grana Padano, and salt. Mix until dough is firm but pliable (similar to pasta dough but not as smooth due to the bread crumbs). Add a little chicken broth if dough is too firm or a few more bread crumbs if it is too soft. Shape the passatelli right away or refrigerate the dough.*

To shape passatelli, flatten dough on a floured work surface. Roll dough into an oval shape about 1/8 inch to 1/4 inch thick. Cut the dough lengthwise in 1/4-inch strips to form long flat noodles. Cut the long noodles crosswise into 3-inch lengths.

Bring 12 cups chicken broth to boiling in a 6- to 8-quart Dutch oven. Drop in the passatelli and stir. Return to boiling. Cook the passatelli for 3 minutes, then stir in the spinach leaves. Return the broth to boiling and cook about 2 to 3 minutes more or until the passatelli are tender and the spinach has wilted. Stir in shredded chicken and heat through. Remove the Dutch oven from the heat and stir in 1 cup freshly grated Parmigiano-Reggiano or Grana Padano. Pour the soup into a heated tureen. Ladle soup into warm bowls. Top each serving with additional cheese, if desired.

Makes 12 appetizer servings

*Note: Passatelli dough may be made the day before shaping. Cover in plastic wrap and store in the refrigerator. Remove from refrigerator, cut, and let passatelli stand at room temperature, covered with a kitchen towel, for a few hours before cooking. Or refrigerate the dough strips, covered with plastic wrap, for up to 2 days. You can also freeze passatelli in an airtight container for up to 2 months.