- 3/4 cup finely chopped white and pale green part of leek, washed well (about 1 leek)
- 2 tablespoons olive oil
- 1 garlic clove, chopped
- 1 small russet (baking) potato, peeled, grated coarse (about 3/4 cup), and reserved in water to cover
- 2 cups low-salt chicken broth
- 2 cups packed arugula, washed well and spun dry
- 3 tablespoons half-and-half or heavy cream
- 1 slice of homemade-type white bread, cut into 1/2-inch cubes
- 1 small plum tomato, seeded and diced, for garnish
- In a small heavy saucepan cook the leek with salt and pepper to taste in 1 tablespoon of the oil over moderate heat, stirring, until it is softened, add the garlic, the potato, drained, and the broth, and simmer the mixture, covered, for 8 to 10 minutes, or until the potato is very soft. Stir in the arugula, simmer the mixture, covered, for 1 minute, and in a blender purée it in batches for 2 minutes, or until it is completely smooth. Transfer the purée to a metal bowl set in a larger bowl of ice and cold water, stir in the half-and half, and chill the soup, stirring occasionally, for 10 minutes, or until it is cold.
- While the soup is chilling, in small heavy skillet cook the bread cubes in the remaining 1 tablespoon over moderate heat, stirring, until they are browned, transfer the croutons to paper towels, and season them with salt. Divide the soup between 2 bowls and top it with the croutons and the tomato.