- 2 tablespoons unsalted butter
- 2 medium leeks, white and tender green parts, coarsely chopped
- 1 1/4 pounds Yukon Gold potatoes, peeled and cut into 1/2-inch dice
- Salt and freshly ground pepper
- 1 quart chicken stock or low-sodium broth
- 1 quart water
- 8 cups packed radish greens (from 2 pounds radishes)
- 1 cup crème fraîche
- 3 tablespoons finely chopped chives
- Melt the butter in a large saucepan. Add the leeks and potatoes, season with salt and pepper and cook over moderately low heat, stirring occasionally, until the leeks are softened, about 8 minutes. Add the chicken stock and water and bring to a boil over high heat. Reduce the heat to moderately low and simmer until the potatoes are tender, about 15 minutes. Add the radish greens and crème fraîche and simmer for 2 minutes longer.
- Working in batches, puree the soup in a blender on low speed until smooth and flecked with bits of green. Transfer to a large bowl, season with salt and pepper and refrigerate, stirring occasionally, until chilled, about 1 hour. Ladle the chilled soup into bowls, top with the chives and serve.
The soup can be refrigerated for up to 2 days.
A crisp, dry white or sparkling wine will contrast with the creamy soup and blend with the slightly bitter greens. Try a simple French vin de pays or an Italian Prosecco.