Step 1

Bring the chicken stock to a simmer in a soup pot.

Step 2

Put the bread crumbs, cheese, salt, and nutmeg in an electric mixer fitted with the paddle attachment. Mix on low speed to combine the dry ingredients, then add the lemon zest. Increase the speed to medium, and add the eggs one at a time, continuing to mix until everything comes together to form a thick dough.

Step 3

To make the passatelli, switch to the meat-grinder mixer attachment with the largest-holed die (or set up a countertop meat grinder). Push the dough through the grinder, cutting with a knife into 2-to-3-inch strands as they come out the other end of the grinder. Lay strands on a baking sheet lined with parchment, and continue until all of the dough is used.

Step 4

Once all the dough is used, drop the passatelli into the simmering stock, and stir. Simmer until the strands are cooked through, about 1 to 2 minutes. Ladle out bowls of passatelli and broth, passing more grated cheese for serving.