Creamy Fennel and Greens Soup

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.