This dinner comes right from the grill and features all the classics -- steak, potatoes, and salad.
Place steak in baking dish with 1/2 cup Vinaigrette. Let marinate at room temperature 15 minutes or up to 1 hour. Heat grill to high; lightly oil grates. Lift steak from marinade; place on grill and cover. Cook, turning once, until meat is done, 3 to 4 minutes per side for medium-rare. Remove from grill; cover loosely with aluminum foil. Let rest 10 minutes before slicing.
Meanwhile, make Potato Salad: In a medium bowl, whisk together mayonnaise, vinegar, parsley, scallions, and garlic; season with salt and pepper. Add potatoes and gently mix until coated; set aside.
Make Romaine Salad: In a large bowl, toss half the romaine with 2 to 3 tablespoons Vinaigrette. Reserve remaining half (not dressed) for Cobb Salad. Serve sliced steak with Potato Salad and Romaine Salad.
Less tender cuts of steak, such as flank steak, should be thinly sliced against the grain. Secure steak with tongs, and use a chef's or carving knife. Slice downward on an angle with long strokes.