Time: 30 minutes. The venerable vichyssoise, but without cream and with spinach--making it a beautiful electric green and good for your waistline.
1 pound leeks
2 tablespoons butter
1/2 teaspoon salt
4 cups vegetable or chicken broth
1 large (12 oz.) Yukon Gold potato, peeled and chopped
1 pound spinach, roots and stems discarded
1 teaspoon salt
1/2 teaspoon freshly ground black pepper
About 1 cup croutons
How to Make It
Slice leeks crosswise and immerse in a large bowl of water to rinse off dirt; lift out to a colander, leaving dirt behind, and rinse again in fresh water if necessary. In a large saucepan over medium-high heat, melt butter. Add leeks and salt and cook until limp, stirring often, about 5 minutes. Add broth and potato. Bring to a boil, covered; reduce heat and simmer until potatoes are tender when pierced, 10 to 15 minutes. Add spinach and cook until wilted, about 1 minute.
Purée in a blender, in batches if necessary, holding lid down with a towel. Pour back into saucepan and thin with more broth if you like; reheat until hot. Season with salt and pepper. Divide soup between 4 serving bowls and top each with about 1/4 cup croutons.