Grilled Flank Steak With Horseradish Sauce Recipe

• 1 lb beef flank steak
• 2 Tbsp. reduced-sodium soy sauce
• 1 Tbsp. red wine vinegar
• 2 x garlic cloves chopped
• 1/2 tsp freshly-grnd black pepper
• 1 c. nonfat lowfat sour cream
• 1 Tbsp. prepared horseradish
• 1 Tbsp. Dijon mustard
• 1/4 c. finely-minced fresh parsley
• 1/2 tsp salt
• 6 x sourdough rolls split
• 6 x romaine lettuce leaves

Directions