Active Time

　　20 min

　　Total Time

　　1 hr

　　Soup is a great way to use up leftover greens, especially the leafy tops of beets or turnips, which too often get tossed in the compost pile. In this suave, satisfying soup, braising beet tops and collard greens (left over, respectively, from Smoked–Sable Tartare with Beets and Watercress and Wild–Mushroom Bundles ) with fennel and onion mellows the greens' hearty flavor and brings out a surprising smoothness (heightened by the cream stirred in at the end). Adding the spinach just before blending helps keep the color bright.

　　

Ingredients

Makes 6 servings

　　1 tablespoon olive oil

　　1 tablespoon unsalted butter

　　1 fennel bulb, trimmed and chopped

　　1 small onion, chopped

　　1 pound mixed dark leafy greens such as collard and beet, coarse stems and center ribs discarded and leaves chopped

　　6 cups water

　　3 cups baby spinach (2 ounces)

　　1/2 cup heavy cream

　　1 tablespoon fresh lemon juice

　　Garnish: fennel fronds or chopped dill

　　

Step 1

Heat oil and butter in a 6-quart heavy pot over medium heat until foam subsides. Add fennel, onion, 3/4 teaspoon salt, and 1/8 teaspoon pepper and cook, stirring occasionally, until softened and lightly browned, 7 to 8 minutes.

　　

Step 2

Add leafy greens (but not spinach) and water to pot and simmer, covered, until greens are tender, about 30 minutes. Stir in spinach and cook, uncovered, just until wilted, about 1 minute.

　　

Step 3

Purée soup in batches in a blender (use caution when blending hot liquids) until smooth, then return to pot. Stir in cream and lemon juice and reheat over low heat. Season with salt.

　　

Cooks' note:

Step 4

Soup can be made 2 days ahead and chilled (covered once cool). Reheat or serve cold.