Flat Iron Steak Recipe

Trim and Pat Dry

Remove the flat iron steak from the refrigerator 30 minutes before cooking to come to room temperature. Trim any excessive fat or silver skin from the surface if present. Pat the steak dry on both sides with paper towels.

Season

Combine kosher salt, black pepper, garlic powder, and smoked paprika. Evenly rub the spice mixture over both sides of the steak, pressing gently so it adheres.

Marinate briefly

Whisk together olive oil, soy sauce, worcestershire sauce, lemon juice, and chopped rosemary. Place the seasoned steak in a shallow dish or zip-top bag and pour the marinade over it, turning to coat. Let rest at room temperature for 15–20 minutes (or in the refrigerator up to 2 hours).

Preheat pan or grill

Heat a cast-iron skillet or heavy-bottomed pan over high heat until very hot (about 5 minutes), or preheat a grill to high. If using a pan, add a thin film (about 1 tsp) of neutral oil with a high smoke point and let it shimmer.

Sear the steak

Remove the steak from the marinade and let excess drip off (discard marinade). Place the steak in the hot pan or on the grill. Sear without moving for 3–4 minutes until a deep brown crust forms. Flip and sear the other side 3–4 minutes for medium-rare (internal temperature 125–130°F / 52–54°C). Adjust time +/- 1–2 minutes for desired doneness.

Finish with butter

During the last 1 minute of cooking, reduce heat to medium-low (or move steak to indirect heat on the grill). Add the unsalted butter to the pan and spoon the melted butter over the steak continuously (basting) for about 30–60 seconds. Sprinkle red pepper flakes if using.

Rest and slice

Transfer the steak to a cutting board and let rest for 8–10 minutes to redistribute juices. Slice the steak thinly across the grain into 1/4-inch slices. Sprinkle chopped parsley on top and finish with a squeeze of lemon juice if desired.

Arrange sliced flat iron steak on a platter with lemon wedges and crostini or fries alongside for a happy hour presentation. Serve warm. Leftovers keep refrigerated up to 3 days.