This clever version of leek and potato soup comes from Cook's Illustrated, one of the best cooking magazines out there -- if you enjoy knowing why things cook the way they do. The folks at CI came up with a version of this soup that is rich and creamy, but doesn't rely on any fatty cream. Instead, the creamy texture comes from including some bread crumbs into the soup before pureeing - brilliance! And tasty to boot!
Creamy Leek-Potato Soup
4 medium leeks, white and light-green parts both
2 c chicken or vegetable stock
2 c water
4 T (1/2 stick) unsalted butter
1 medium onion, chopped (about 1 c)
1 small russet potato (about 6 oz), peeled, halved lengthwise, and cut into 1/4" slices
1 bay leaf
1 4" sprig fresh thyme or tarragon
1 large slice of high-quality sandwich bread, lightly toasted, and torn into 1/2" pieces
Separate leeks into white and light green parts. Begin with the dark green parts -- half them, rinse them well, and cut them into 2" pieces.
Add the dark green leek pieces to the stock and water. Bring to a boil over high heat.
Reduce heat to low, cover, and simmer 20 minutes. Strain (or lift) solids from the stock and discard solids.
Halve the white parts of the leek lengthwise. Rinse well and slice thin. You should have about 4 c of white leeks.
Melt butter in a stockpot or Dutch oven. When butter foams, stir in sliced leeks, onion, and 1 tsp salt. Reduce heat to low and cook, stirring frequently, until vegetables are softened -- about 10 minutes.
Increase heat to high. Stir in reserved stock, potato, bay leaf, and herb sprig. Bring to a boil. Reduce heat to low and simmer until potatoes are tender, about 10 minutes.
Add toasted bread and simmer until bread is completely saturated and starts to break down, about 5 minutes.
Cook's Illustrated also recommended lightly frying leek strips as a garnish. This involves using the white parts only. Cut them into thin strips, dust with flour, salt and pepper and lightly fry in olive oil (about 6 minutes). Drain on paper towels, and use as garnish in the soup.