1. Heat oven to 450 degrees F.
2. In a large bowl, stir together tomatoes, zucchini, squash, fennel, onion, garlic, 1/2 tablespoon of the thyme, 1/8 teaspoon of the salt, the pepper and broth; set aside.
3. Lay four large pieces of foil or parchment paper (each 16 inches long) on work surface. Place 1-1/2 heaping cups vegetable mixture on lower half of each piece. Place fish on top of vegetables and sprinkle with remaining 1/2 tablespoon thyme and 1/8 teaspoon salt. Place 1 teaspoon butter on top of each fillet. Fold foil or parchment over fish and fold edges to create a sealed packet. Place packets on a rimmed baking sheet, overlapping if necessary.
4. Bake at 450 degrees F for 20 minutes or until fish is cooked through and veggies are tender. Cut open packets and slide contents onto plates; serve immediately.
Servings Per Recipe: 4; Amount Per Serving: cal.(kcal): 230, Fat, total(g): 4, chol.(mg): 55, sat. fat(g): 1, carb.(g): 9, fiber(g): 3, pro.(g): 37, sodium(mg): 300, Percent Daily Values are based on a 2,000 calorie diet.