Directions

1. Remove the stalks from each fennel bulb and discard. Cut the bulbs in half lengthwise through the core. Remove most (but not all) of the core by cutting a V-shaped wedge, leaving the wedges intact. Cut each piece into 2, 3, or 4 wedges, depending on the size of the bulb.
   
2. Preheat the oven to 375 degrees F. Arrange the wedges, cut side up, in a gratin dish just large enough to hold them snugly in a single layer. Pour the chicken broth and wine over the fennel, then sprinkle with 1 teaspoon salt and 1/4 teaspoon pepper.
   
3. Dot with 1 tablespoon of diced butter. Cover the dish tightly with aluminum foil and bake for 35 to 45 minutes, until the fennel is tender.
   
4. Meanwhile, combine 1 1/2 tablespoons melted butter, panko, Parmesan, Gruyere, parsley, zest, 1/2 teaspoon salt, and 1/4 teaspoon pepper. Remove fennel from the oven and raise the oven temperature to 425 degrees F.
   
5. Sprinkle topping evenly on top and return to the oven. Bake uncovered for 30 minutes, until the topping is browned. Serve hot or warm.