Prep: 15 minutes

Cook: 45 minutes

Makes: 6 servings

3 cups sweet potato, peeled, cut into 1-inch chunks

1 cup leeks, white parts only, cut into ½-inch pieces

5 cups whole milk

2 bay leaves

2 teaspoons kosher salt

1 tablespoon curry powder, optional

1/8 teaspoon cayenne pepper

6 to 8 tablespoons cold unsalted butter, cut up

1. Simmer: Load all ingredients except butter into a large saucepan. Simmer, stirring regularly to prevent scorching, until sweet potatoes turn tender, about 45 minutes. (If the soup looks curdled, don't worry; it will be silky smooth in the end.)

2. Blend: Pull out bay leaves. Pour soup into a blender (or work in batches). Blend completely smooth, adding butter one chunk at a time through the slot in the lid.

3. Serve: Scoop into small bowls and serve at once. Or chill and reheat over low heat, stirring often.

Provenance: Adapted from a recipe by Paul Fehribach, chef and co-owner of Big Jones restaurant in Chicago.