Coarsely grate one zucchini and refrigerate

Slice remaining zucchini into thin, crosswise slices

Heat oil in a 5 to 6 quart saucepan, over medium- high heat

Add onions, and cook, stirring often, until onions become translucent, about 10 minutes

Add sliced zucchini and one cup of broth

Bring to a boil over a high heat, reduce heat, cover, and simmer until zucchini is tender, about 15 minutes. In a blender or food processor, puree cooked zuc- chini mixture until it reaches a smooth consistency

Return to pan and stir in remaining broth

Heat until the mixture just boils, remove from heat and stir in pesto. Ladle into bowls and garnish with remaining zucchini and fresh basil sprigs

Pass with freshly grated Parmesan

Serves 6 to 8.