On baking sheet, toss broccoli, shallot and oil; season. Roast at 425°, turning once, until charred in spots and crisp-tender, 25 minutes; reserve 1/2 cup small florets. In blender, puree roasted broccoli with stock, spinach, Parm, zest and juice. In pot, heat soup over medium until warm; season. Top with reserved florets.
Bright Idea: Tossing a handful of fresh spinach into the blender gives you that bright- green hue.