1. Prepare the Steak:
Take the flat iron steak out of the refrigerator and let it sit at room temperature for about 30-45 minutes before cooking. This helps ensure even cooking.
2. Preheat Your Cooking Surface:
Preheat a grill, cast-iron skillet, or stovetop grill pan to medium-high heat. If using an oven for finishing, preheat it to 400°F (200°C).
3. Sear the Steak:
If using a grill, place the steak directly on the grates. Cook for about 4-5 minutes on one side without moving it, allowing nice grill marks to form.
If using a skillet, add a tablespoon of high smoke-point oil (like canola or grapeseed) and heat until shimmering. Place the steak in the skillet and sear for about 4-5 minutes on one side.
4. Flip and Continue Cooking:
Flip the steak and continue cooking for another 4-5 minutes for medium-rare. Use an instant-read thermometer to check the internal temperature; it should read around 130°F (54°C) for medium-rare.
5. Rest the Steak:
Remove the flat iron steak from the heat and let it rest on a cutting board for 5-10 minutes. This resting period allows the juices to redistribute, ensuring a juicier steak.
6. Slice and Serve:
Slice the flat iron steak against the grain into thin strips for maximum tenderness. Serve with your favorite sides and consider drizzling with a bit of high-quality olive oil or sprinkling with flaky sea salt for added flavor.