Pan Seared Flat Iron Steak

PREP TIME	REST TIME	COOK TIME	TOTAL TIME
10 mins	45 mins to 24 h	10 mins	1 to 24 hours

Pan-seared flat iron steak, infused with color from the butter and flavor from herbs, is an excellent alternative to thick ribeye or strip steak. This simple and quick recipe allows you to experience the best of a flat iron steak—tender and juicy inside and perfectly seared on the outside. The butter helps create a delightful brownish golden crust and infuses the flat iron steak with rosemary or thyme and garlic flavors.

Below, I present a step-by-step guide to cooking a flat iron steak in a cast iron skillet on a gas stove. This method is a great alternative to grilling when the weather isn’t ideal for outdoor cooking. So, let’s begin by gathering the necessary ingredients.

The Ingredients You’ll Need

• A Flat Iron Steak (Avoid butterflied flat iron steaks or thinly cut; choose the thicker ones)
• 1 tablespoon high-smoke point oil (I always recommend avocado oil)
• 1 teaspoon kosher Salt
• 1 teaspoon finely ground pepper
• ½ stick of unsalted butter (About 56.7 grams)
• 2-3 Garlic cloves
• 2-3 thyme or rosemary springs

The Tools You’ll Need

• Cast Iron Skillet
• Tongs
• Instant Read Thermometer

How to Pan Sear Flat Iron Steak

Pan-searing a flat iron steak on the stove sounds pretty simple, but trust me, there are a few key things you’ve got to watch out for. It’s easy to mess up – like adding your butter too soon or getting the seasoning all wrong, which can ruin your meal. Don’t worry, though. I’ve compiled a detailed, step-by-step guide with photos to help you perfectly pan-sear your flat iron steak.

Note: I used a flat iron steak weighing about 1 pound (454 grams) for this recipe. I seasoned it with salt and pepper, letting the flat iron steak’s distinct beefy flavor shine.

Step 1: Prepare the Flat Iron Steak

Start by patting the flat iron steak dry with paper towels. Then, select a salting method based on your time and desired results.

• Option 1: Short on time? Just salt the flat iron steak and let it sit at room temperature for at least 45 minutes before cooking. This resting time allows the flat iron steak to reabsorb the most moisture on its surface, which helps achieve a better crust.
• Option 2: If you’re not in a rush and want the best flavor and crust, salt the flat iron steak and leave it overnight in the refrigerator, uncovered on a rack. Remove it from the refrigerator for at least 30 minutes before cooking the next day.

Remember, don’t cook the flat iron steak straight from the fridge. If you’re curious why, check out my guide on How Long to Leave Steak out Before Cooking.

Step 2: Preheat the Skillet

Get your cast iron skillet nice and hot over medium-high heat, letting it sit for 2-3 minutes. Then, add some oil with a high smoke point (about two teaspoons or one tablespoon should do), and give it another minute to heat up. By this time, the pan should be at least 400°F (204°C), which is perfect for pan-searing flat iron steak.

In the meantime, season the flat iron steak all over with pepper.

Step 3: Place the Flat Iron Steak in the Skillet

Place the seasoned steak in a very hot skillet. Cook by flipping it every 30 seconds. Once the flat iron steak’s internal temperature reaches 90°F (32°C), turn down the heat to medium-low and move on to the next step.

Note: Flipping the flat iron steak regularly helps it cook more evenly and lets you keep a better eye on both sides.

Step 4: Add the Herbs, Garlic, and Butter

Add the butter, a few garlic cloves, and a sprig of thyme or rosemary to the pan and wait until the butter melts. While you’re waiting, sear the sides of the flat iron steak.

Once the butter’s melted, move the flat iron steak to the other side of the pan. Then, grab a spoon, tilt the pan slightly to gather the butter, and gently baste the flat iron steak with this butter, keeping a steady rhythm for 30 seconds on each side. Alternatively, you can gather the butter in one spot and place the flat iron steak right in it, flipping it every 30 seconds until it’s about 20-25°F (11-14°C) below your target doneness, then remove it from the pan. Oh, and don’t forget to turn off the burner – you don’t want the leftover butter to burn. We’re going to use that butter later on.

For example, if you want your flat iron steak to reach 130-135°F (54-57°C), take it off the heat at 110°F (43°C). Wondering why so early? Check out the FAQ section below for a good explanation. Now, let’s get back to the recipe.

Step 5: Let the Pan Seared Flat Iron Steak Rest

Remember, the last step is as important as everything else you’ve done. After you take the flat iron steak off the pan, don’t rush it. Let it chill out for about 5 minutes. If it’s thick, give it more time (6-7 minutes is enough).

Once your flat iron steak is done and sliced, remember to drizzle the butter from the pan over it. If the butter has gone cold, give it a quick heat-up first. Then, top it off with your fried garlic and herbs.

Pan Seared Flat Iron Steak FAQs

When’s the best time to take a flat iron steak off the pan? 

Let me give you an example. I pulled my flat iron steak off the heat when it reached 111°F (44°C). Then, in about 5-6 minutes, its temperature shot up to 132°F (56°C), a jump of 21°F (12°C)! (Check out the photos below).

Many recipes suggest taking the steak off the heat 5-10°F (2-5°C) before the target temp. But I’ve found that’s not always the best idea. If you take it off at 120°F (49°C), don’t be surprised if it ends up around 140°F (60°C) inside! Of course, remember that this mainly applies when cooking a steak in a pan or grill at really high temperatures. With the reverse sear method, this issue either doesn’t come up or is barely noticeable.

To learn more, see my full guide on How Long to Let Steak Rest After Cooking.

What is the ideal thickness for a flat iron steak when pan-searing?

The thickness of the flat iron steak depends on how you like your steak.  If you aim for medium-rare (130-140°F/54-60°C), you’ll want your flat iron steak to be at least 1.25 inches thick. Even better, go for around 1.5 inches (3.175 cm) if you can. Here’s the thing: if the flat iron steak is too thin, it will cook all through before the outside has a chance to get that delicious, crispy crust. Check out the example below.

The flat iron steak on the left was cooked to 132°F (56°C), and the one on the right to 124°F (51°C). If you look at the photo, you’ll notice the right flat iron steak’s crust looks way better. That flat iron steak is thicker, so I had to cook it longer. I know this isn’t the perfect comparison since you’d ideally cook flat iron steaks of different thicknesses to the same doneness to see the difference. But still, the photo does a good job of showing what I’m talking about.

What is the ideal doneness for a flat iron steak?

Based on my experience and preference, medium-rare is the best way to cook a flat iron steak. But of course, everyone has their taste. Some people like their flat iron steak a bit more done, and that’s fine. Interestingly, it stays tender and juicy even if you cook it more. So, this cut is a great choice if you like medium or medium-well steak.

What’s the best type of pan for searing a flat iron steak?

Technically, you can sear a flat iron steak in any pan. But let’s be real: Some pans are better for this job. Cast iron skillets are awesome for this because they hold onto heat well, which is exactly what you need for a perfect sear. Not into cast iron? That is no problem. Stainless steel and carbon steel are good alternatives.

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More Pan-Seared Steak Recipes To Try

• Pan Seared Ribeye Steak
• Pan-Seared Top Blade Steak
• Pan Seared Hanger Steak
• Pan-Seared Filet Mignon
• Pan Seared Strip Steak