In a zip-top plastic bag, combine vinegar, 1 tablespoon olive oil, garlic and thyme. Add steak and seal, pressing out air. Shake bag so steak is coated with marinade. Refrigerate for 4 hours or overnight, turning steak every few hours.

Heat a grill pan, cast-iron or nonstick skillet, or grill over medium-high heat. Brush steak lightly with remaining 1 teaspoon oil. Grill for 4 to 5 minutes per side for medium-rare, brushing with marinade as it cooks. Transfer to a cutting board, and let rest for 5 minutes. Discard remaining marinade. Cut into thick slices and serve. Makes 3 servings.

PER SERVING: Calories 289 (68% fat) Fat 22 g (7 g sat) Chol 71 mg Sodium 59 mg Carbohydrates 2 g Protein 21 g

SOURCE: Cox News Service/Adapted from The South Beach Diet Parties and Holidays Cookbook by Arthur Agatston (Rodale, $25)