Potato Leek Soup

Wash the leeks

Leeks grow in sand and it sits packed between the layers, so rinsing the outside does nothing. Slice them first, then drop the slices into a large bowl of cold water and swish them hard with a hand. Let the bowl sit 2 minutes. Lift the leeks out with fingers or a spider and move them to a colander, leaving the grit on the bottom of the bowl. Pour the water off and repeat if the bowl was gritty.

Sweat the leeks

Melt the butter in a large pot over medium low heat. Add the leeks and 1/2 teaspoon of the salt. Cook, stirring often, for 10 to 12 minutes, until fully limp and sweet. Any browning turns the finished soup gray and toasted tasting, so drop the heat if the pot starts to color.

Add the potatoes and stock

Stir in the potatoes, the remaining salt, the bay leaves, and the pepper. Pour in the stock. Bring to a boil, then simmer partly covered for about 20 minutes. The potatoes are done when a paring knife slides into a cube with no resistance.

Blend briefly

Remove the bay leaves. Potato starch turns gluey when it is beaten, so keep the blending short. Submerge an immersion blender fully and pulse it around the pot for 20 to 30 seconds, either to a chunky partial puree or just to smooth. A food mill gives the silkiest result with no risk. A countertop blender will make wallpaper paste out of this soup, so avoid it.

Season and finish

Set the pot over low heat. Stir in the cream if using and warm it without boiling. Thin with stock to the consistency preferred, taste, and add salt. Scatter chives over each bowl.

Storage. Keeps 4 days refrigerated. It thickens as it sits, so loosen it with stock when reheating.