Under 30 Minutes
Broiled Flank-Steak Sandwiches
- 1/4 cup sour cream
- 1/4 cup mayonnaise
- 2 tablespoons prepared horseradish
- 1 tablespoon grainy mustard
- Coarse salt and freshly ground black pepper
- 1 1/2 pounds flank steak
- 3 tablespoons extra-virgin olive oil
- 1 bunch watercress, tough stems trimmed
- 1 tablespoon freshly squeezed lemon juice
- 4 thick slices rustic bread, toasted
- Roasted Peppers with Garlic and Basil, or store-bought roasted bell peppers, if you prefer
Make horseradish sauce: In a small bowl, whisk together sour cream, mayonnaise, horseradish, and mustard. Season with salt and pepper. Cover with plastic wrap; refrigerate while preparing steak.
Heat broiler, with rack 6 inches from heat. Season steak well on both sides with salt and pepper; rub with 2 tablespoons oil. Place on a roasting pan fitted with a rack. Broil 6 minutes on each side for medium-rare. Let rest 5 minutes before slicing 1/4 inch thick.
Place watercress in a bowl; toss with remaining tablespoon oil and the lemon juice. Season with salt and pepper. Serve on toasted bread, topped with steak, horseradish sauce, and roasted peppers.