Ingredients

  • 2 packages (10 ounces each) frozen spinach, thawed
  • 1/4 cup packed fresh flat-leaf parsley leaves, coarsely chopped
  • 1/4 cup grated Asiago cheese (2 ounces)
  • 2 tablespoons capers, drained and rinsed
  • 2 tablespoons balsamic vinegar
  • 1 garlic clove, minced
  • 1/4 teaspoon crushed red-pepper flakes
  • Coarse salt and freshly ground pepper
  • 1 pound flank steak
  • 2 teaspoons olive oil

Method

  • Heat broiler, with rack set 4 inches from heat source.
  • Line a rimmed baking sheet with aluminum foil.
  • Squeeze spinach in a clean kitchen towel (or a double layer of paper towels) to remove as much liquid as possible.
  • Combine spinach, parsley, cheese, capers, vinegar, garlic, and red-pepper flakes in a bowl.
  • Season with salt and pepper; toss to combine.
  • To butterfly steak, lay it on a cutting board with a short side facing you.
  • Using a long knife, slice steak horizontally, leaving one side intact; open up like a book.
  • Cut several 12-inch pieces of kitchen twine; space evenly underneath steak.
  • Spread spinach mixture down center of meat.
  • Roll steak over mixture, pressing firmly to compact filling; tie twine to secure roll.
  • Cut roll in half crosswise.
  • Place halves, seam side down, on prepared baking sheet; rub with oil, dividing evenly, and season with salt and pepper.
  • Broil steak until browned on all sides, turning as needed with tongs, 8 to 10 minutes for medium-rare; let rest, covered loosely with aluminum foil, 10 minutes.
  • Remove string; slice steak 1/2 inch thick.