Preheat oven to 450 degrees F. For Sorrel Pesto, in a food processor bowl or blender container combine 1/4 cup of the olive oil, sorrel, pine nuts, and garlic. Cover; process while drizzling in up to 1/4 cup remaining olive oil, scrapping down sides of processor as necessary. Season to taste with salt and pepper. Set aside.
Brush a roasting pan with olive oil. Place fish fillets in prepared pan. Lightly brush fish with olive oil; sprinkle with salt and pepper. Roast, uncovered, for 12 minutes or until fish flakes easily when tested with a fork. Serve with Sorrel Pesto. Makes 8 servings with about 2 tablespoons pesto per serving.