1. Preheat oven to 400°.
2. Place tomatoes and leeks in a roasting pan; drizzle with 2 tablespoons olive oil, vinegar, rosemary, 1/4 teaspoon sea salt, and 1/4 teaspoon pepper. Toss gently to coat. Roast at 400° for 25 minutes, stirring leeks once halfway through cook time or until leeks are tender and tomato begins to shrivel.
3. Season fish fillets with 1 tablespoon olive oil, 1/2 teaspoon sea salt, and 1/4 teaspoon pepper. Melt butter with remaining 1 tablespoon olive oil in a large nonstick skillet over medium-high heat. Place fillets, skin side down, in pan; reduce heat to medium, and cook for 4 minutes, without moving fish. Carefully turn fillets over; and drizzle lemon juice over fish. Cook 2 to 3 minutes or until fish flakes easily with a fork, spooning pan liquid over fish while cooking. Remove fish from pan, and cover loosely to keep warm.
4. Add wine and broth to pan, and increase heat to medium-high. Reduce sauce to 1/4 cup (about 5 minutes) and until sauce is slightly thick and bubbly.
5. Place fillets on a platter or four individual plates, spooning sauce over and around fish; arrange leek and tomato mixture on each plate, and garnish, if desired. Serve immediately.