• Peel the shallot and coarsely chop.

In a bowl, combine the shallot, egg, chickpea flour, dumpling spice blend, and ground chicken. Season generously with salt and pepper, and mix well. Refrigerate until ready to use.

• Cut the leek in half lengthwise and then into ¼-inch-thick half-moon slices. Soak in a bowl of water and allow any dirt to settle at the bottom.
• Cut the celery into ¼-inch-thick diagonal slices.
• Cut the carrot in half lengthwise and then into ¼-inch-thick diagonal slices.
• Remove any stems from the herb mix and finely chop the leaves.

In a pot over medium heat, warm 2 tablespoons oil until hot but not smoking. Lift the leeks from the water, add to the pan, season with salt and pepper, and cook until just soft, 3 to 4 minutes. Add the celery and carrots, and cook, stirring occasionally, until tender, 2 to 3 minutes.
Add the chicken stock and 2½ cups water, and bring to a boil. Add the pappardelle, reduce to a simmer, and cook until the pasta is just tender, 5 to 7 minutes. While the pappardelle cooks, shape the dumplings.

With a spoon, scoop about 1½ tablespoons of the ground chicken mixture. Press another spoon on top of the meat to to shape it into a oval. Pass the chicken back and forth several times to make smooth, evenly shaped dumplings. Add each dumpling to the pot immediately after it’s formed and simmer until the dumplings are firm and cooked through, 6 to 8 minutes. Stir the herb mix into the soup and remove from the heat. Season to taste with salt and pepper.

Transfer the soup to individual bowls and serve.