The solution: In keeping with our goal for a rustic soup, we decided not to puree the soup but to leave it full of chunks of potato and even some pieces of leek. The potatoes best suited to this task were the waxy, low-starch Red Bliss. High-starch, low-moisture baking potatoes disintegrated, as did medium-starch Yukon Golds—only not quite as quickly as the bakers. We left pieces of leek in the soup not only for texture but for flavor. While many versions of potato-leek soup seem to give only passing thought to the leeks, we felt that their flavor should predominate.
Timing is also crucial in potato-leek soup. Undercook the soup and the flavors won’t meld; overcook it and you’ll have a mixture of broken-down bits with little flavor or bite. Consequently, our real breakthrough with this soup came in the province of technique and timing. We knew that potatoes and leeks would need different simmering times. Stewing the leeks over a low flame to coax out as much flavor as possible, we added the potatoes later, with the broth, then simmered until almost tender. We then removed the pot from the heat and allowed the potatoes to finish cooking in the hot broth, thereby preventing them from overcooking and getting mushy.

COUNTRY-STYLE POTATO-LEEK SOUP
Makes about 11 cups, serving 6 to 8

Leeks differ. If yours have large desirable white and light green sections, use 4 pounds of leeks; if they’re short on these parts, go with 5 pounds.

6 tablespoons unsalted butter
4–5 pounds leeks (see note above)
1 tablespoon all-purpose flour
5¼ cups chicken stock or canned low-sodium
chicken broth
1 bay leaf
1 ¾ pounds red potatoes (about 5 medium), peeled
and cut into ¾-inch dice
Salt and ground black pepper

1. Cut off roots and tough dark green portion of leeks, leaving white portion and about 3 inches of light green. Clean leeks following illustrations at left. Slice in half lengthwise and chop into 1-inch sections. (You should have about 11 cups).
2. Heat butter in Dutch oven over medium-low heat until foaming; stir in leeks, increase heat to medium, cover and cook, stirring occasionally, until leeks are tender but not mushy, 15 to 20 minutes; do not brown. Sprinkle flour over leeks and stir to coat evenly ; cook until flour dissolves, about 2 minutes. Increase heat to high; whisking constantly, gradually add stock. Add bay leaf and potatoes; cover and bring to boil. Reduce heat to medium-low and simmer, covered, until potatoes are almost tender, 5 to 7 minutes. Remove pot from heat and let stand until potatoes are tender and flavors meld, 10 to 15 minutes. Discard bay leaf, season with salt and pepper; serve immediately.

COUNTRY-STYLE POTATO-LEEK SOUP WITH KIELBASA

Eight ounces of cooked ham, cut into ½-inch dice, can be substituted for the sausage, if desired. Whichever you choose, season the soup with care, since both ham and kielbasa are fully seasoned.

Follow recipe for Country-Style Potato-Leek Soup. Before removing pot from heat, stir in 8 ounces kielbasa sausage, cut into ½-inch slices.

COUNTRY-STYLE POTATO-LEEK SOUP WITH WHITE BEANS

Follow recipe for Country-Style Potato-Leek Soup, reducing potatoes to 2 medium (about ¾ pound). Before removing pot from heat, stir in 1 cup hot water and 1 cup canned cannellini beans.