NOTES: Use a wide pan in order to have adequate surface area to make the dumplings. You can make the soup through step 4 up to 1 day ahead if you like; cover it airtight and chill. Before serving, bring it to a simmer over medium heat, stirring occasionally, then proceed with making the dumplings (steps 5 and 6). PREP AND COOK TIME: About 1 1/4 hours.
5 russet potatoes (about 2 1/2 lb.), peeled and diced
2 stalks celery (about 4 oz.), rinsed, trimmed, and diced
2 carrots (about 6 oz.), peeled and diced
1 cup all-purpose flour
1/2 cup cornmeal
1 1/2 teaspoons baking powder
1 teaspoon salt
2 teaspoons finely chopped fresh sage leaves
1/3 cup milk
1 large egg plus 1 large egg white, beaten lightly together to blend
2 tablespoons melted butter
How to Make It
In a 6- to 8-quart pan over high heat, bring chicken, broth, and whole sage leaves to a boil. Reduce heat to low, cover, and simmer, skimming off and discarding any foam that rises to the surface, until chicken is no longer pink at bone (cut to test), about 30 minutes.
Meanwhile, cut off and discard root ends and dark green tops from leeks. Cut white and pale green parts in half lengthwise and rinse well under running water, flipping layers to release grit. Thinly slice leeks crosswise.
Lift chicken from broth. When cool enough to handle, pull meat into shreds (discard bones).
Add potatoes, celery, carrots, leeks, and 2 cups water to pan with broth. Bring to a boil over high heat, then reduce heat to medium, cover, and simmer until vegetables are tender when pierced, 20 to 30 minutes. Stir in shredded chicken.
Meanwhile, in a large bowl, mix flour, cornmeal, baking powder, salt, and the chopped sage. Stir in milk, beaten egg and egg white, and the melted butter just until combined.
Drop dumpling batter in 12 to 14 heaping tablespoon portions on the surface of the simmering soup. Cover pan and simmer over medium-low heat (do not allow soup to boil) until a knife inserted into the center of a dumpling comes out clean, about 10 minutes. Ladle hot soup into bowls.