1/2 cup red wine vinegar
1/4 cup soy sauce
3 tsp. Dijon mustard
2 cloves garlic, finely chopped
1 1/2 pounds flank steak
1 cup non-fat sour cream
2 T. prepared horseradish
freshly ground black pepper
1 T. chopped scallions or chives

In a shallow bowl, combine the vinegar, soy sauce, 2 tsp. of Dijon mustard and garlic. Add the flank steak and coat it well with the marinade. Cover and refrigerate for 30 minutes or overnight. Preheat the broiler or grill. In a small bowl, combine the remaining tsp. of mustard, sour cream and horseradish. Season to taste with salt and pepper. (This sauce can be prepared in advance and stored in the refrigerator for up to 3 days.) Broil the steak on each side until medium-rare, about 6 minutes per side. (The steak can be cooked in advance, stored in the refrigerator for up to 2 days and served slightly chilled or at room temperature.) Let the steak rest for 3 or 4 minutes before thinly slicing it on the bias. Garnish the sliced steak with scallions or chives and serve with the horseradish sauce.

Serving Size: 3 to 4 slices
Calories: 232