Ingredients

  • 1 (1-1/2- to 2-pound) flank steak, trimmed of fat and silver skin
  • 3/4 cup olive oil
  • 1/3 cup balsamic vinegar
  • 1 tablespoon water
  • 1 medium garlic clove, peeled and smashed
  • 2 teaspoons packed dark brown sugar
  • 1 1/2 teaspoons finely chopped fresh marjoram leaves
  • 1 1/2 teaspoons kosher salt, plus more as needed
  • 1/2 teaspoon freshly ground black pepper, plus more as needed
  • 3 medium red, orange, or yellow bell peppers (or a combination)
  • 1/4 cup coarsely chopped, pitted green olives
  • 1/2 teaspoon kosher salt, plus more as needed
  • Freshly ground black pepper

Method

  • Heat an outdoor grill to high (about 450 degrees F to 550 degrees F).
  • Season the steak generously with salt and pepper and place it in a 13-by-9-inch baking dish.
  • Place the remaining measured ingredients in a blender and blend until evenly combined, about 30 seconds.
  • Remove 3 tablespoons of the marinade and set it aside for the relish.
  • Pour the remaining marinade into the dish with the steak, turn the steak to coat, and let it marinate at room temperature for 30 minutes, flipping halfway through.
  • Meanwhile, grill the peppers for the relish.
  • Place the bell peppers on the grill.
  • Cover the grill and cook, turning occasionally, until the peppers are blackened and blistered on all sides, about 25 minutes.
  • Transfer the peppers to a large bowl.
  • Cover tightly with plastic wrap or a large plate and let sit until cool enough to handle, about 15 minutes.
  • Meanwhile, grill the steak.
  • Remove the steak from the baking dish and let any excess marinade drip off; discard the marinade.
  • Place the steak on the grill and season it generously with salt and pepper.
  • Cover the grill and cook until grill marks appear on the bottom, about 5 to 6 minutes.
  • Flip the steak and season generously with salt and pepper.
  • Cover the grill and continue to cook until grill marks appear on the bottom and an instant-read thermometer inserted into the middle of the steak registers 125 degrees F to 130 degrees F for medium rare, about 5 to 6 minutes more.
  • Transfer to a large, clean plate and let rest for 10 to 15 minutes.
  • Meanwhile, finish the relish.
  • Transfer the peppers from the bowl to a cutting board.
  • Set the bowl aside, reserving any liquid inside.
  • Use a knife to scrape and peel the skins off; discard the skins.
  • Slice the peppers open and remove the seeds and membranes.
  • Cut the peppers into medium dice and return them to the large bowl.
  • Add the remaining measured ingredients and the reserved marinade and stir until evenly combined.
  • Taste and season with salt and pepper as needed.
  • Thinly slice the steak against the grain, season it with salt and pepper, and serve with the bell pepper relish.