Butterflying a steak is actually quite simple and can be done quickly at home, but you can also ask your butcher to do it.
Ingredients
serves 4
Step 1
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.
Step 2
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.
Step 3
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.
Step 4
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.
