Arrange fennel and onion in a single layer on a jelly-roll pan coated with cooking spray; toss to coat. Bake at 425° for 25 minutes, stirring after 15 minutes. Add chickpeas to vegetable mixture. Bake an additional 20 minutes or until fennel is tender and chickpeas start to brown, stirring after 10 minutes.
Melt butter in a large saucepan over medium heat. Add garlic to pan, and cook for 1 minute, stirring occasionally. Add vegetable mixture, broth, and the next 3 ingredients (through salt) to pan, and bring to a boil. Cook for 3 minutes or until thoroughly heated. Remove from heat, and garnish with parsley. Serve with pita wedges.