Heat the oven to 400 degrees F. Place the fennel, onions and garlic into a large bowl. Add the oil and toss to coat. Spoon the fennel mixture onto 2 rimmed baking sheets.
Roast for 30 minutes or until the fennel mixture is lightly browned, stirring occasionally.
Reduce the oven temperature to 350 degrees F. Stir the fennel mixture, lemon zest, parsley, pine nuts and broth in a large bowl. Add the stuffing and mix lightly. Spoon the stuffing mixture into a greased 3-quart casserole. Cover the casserole.
Bake for 30 minutes or until the stuffing mixture is hot.