thawed and well drained cut into thin strips Cut block of fish crosswise into 4 equal pieces. In a small skillet, cook onion and garlic in hot oil till tender. Remove from heat. Stir in wine, tarragon or basil, salt, and pepper. Return to heat and boil gently about 2 minutes or until most of the liquid has evaporated. Remove skillet from heat and set aside. Place 0.125 of the spinach on four 12x18 inch pieces of heavy foil. Place 1 portion of fish on each portion of spinach. Spoon onion mixture evenly over fish. Top with remaining spinach and the green pepper strips. Bring up long edges of foil and, leaving a litle space for steam expansion, seal tightly with a double fold. Then fold short ends to seal. Grill foil packets, seam side up, directly over medium coals about 20 minutes or till fish flakes easily when tested with a fork. Turn packets over twice. * Per serving: 162 calories, 22 g protein, 6 g carbohydrates, 4 g fat, 49 mg cholesterol, 169 mg sodium, 815 mg potassium.