How to Make It
In a small bowl, mix 1 tablespoon of the olive oil with 1 tablespoon of the lime juice. Stir in the molasses, honey, cracked peppercorns and cayenne.
In another small bowl, mix the remaining 1 tablespoon of lime juice with the garlic, Worcestershire sauce and mustard. Gradually whisk in the remaining 1/4 cup of olive oil and season the vinaigrette with salt and pepper.
Light a grill or heat a grill pan. Season the steak with salt and pepper and grill over high heat for 13 minutes, turning once. Brush the molasses mixture all over the steak and grill for 2 minutes longer for medium-rare meat. Transfer to a cutting board and let stand.
In a small bowl, toss the bread crumbs with the Parmigiano and season with salt and pepper. Thinly slice the flank steak across the grain. Arrange the romaine and red leaf lettuce on a platter and drizzle with the vinaigrette. Scatter the bread crumbs over the salad, top with the steak and serve.