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 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 proves to be 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
To prepare a tender, butter-infused flat iron steak on your stovetop, you’ll need:
- A Flat Iron Steak (Avoid butterflied flat iron steaks or thinly cut)
- High-smoke point oil (I always recommend avocado oil)
- Kosher Salt
- Finely ground pepper
- Unsalted butter
- Garlic cloves
- Fresh Thyme or Rosemary
The Tools You’ll Need
- Cast Iron Skillet
- Instant Read Thermometer
How to Cook Flat Iron Steak on a Stove
Cooking a flat iron steak in a skillet 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 walk you through cooking your flat iron steak in a skillet.
Note: I used a flat iron steak weighing approximately 1 pound for this recipe. I opted to season it with salt and pepper, allowing the steak’s distinct beefy flavor to take center stage.
Step 1: Prepare the Flat Iron Steak
Start by drying off the flat iron steak with some paper towels. Next, give it a good sprinkle of salt on all sides. Let it sit in the fridge for at least 45 minutes or overnight if you have the time. But if you’re in a bit of a rush, no worries – salt it before you cook it.
Step 2: Preheat the Skillet
Get your cast iron skillet nice and hot over medium-high heat, and let it sit there for 3-4 minutes. After that, toss in a bit of oil – about two teaspoons or one tablespoon should do – and give it another minute to heat up.
Before you cook, season the flat iron steak all over with pepper. And if you haven’t salted it yet, now’s the time. Just sprinkle the salt on before you toss the steak in the pan, like a minute before searing, not earlier. If you salt it too early, the steak gets moist on the surface. And trust me, you want it dry if you’re after that perfect crust.
Step 3: Place the Flat Iron Steak in the Skillet
Place the seasoned steak in a very hot skillet and cook it by flipping every 30-60 seconds. Once the internal temperature reaches 100°F (I aim for medium-rare), reduce the heat to medium-low and proceed to the next step.
Note: Regularly flipping the steak helps it cook more evenly. Plus, it lets you keep a better eye on how it’s cooking on both sides.
Step 4: Baste Flat Iron Steak with Butter
Add the butter, some garlic cloves, and a sprig of thyme or rosemary to the pan and wait for the butter to melt. Meanwhile, this is a good time to sear the sides of your steak.
Once the butter’s melted, pop the steak on the other side of the pan. Then, grab a spoon and tip the pan slightly to scoop up the butter from the bottom. Gently baste the steak with this butter. Keep doing it in a steady rhythm, about half a minute to 45 seconds for each side.
Meanwhile, keep an eye on the steak’s temperature. If it’s about 15-20°F away from your target, it’s time to take it out of 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, say you’re aiming for a steak at 130°F. You’ll want to pull it off the heat when it hits about 110-115°F. Why so soon? There’s a good explanation for that in the FAQ section down below. Alright, back to the recipe now.
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 steak off the pan, don’t rush it. Let it chill out for about 5 to 10 minutes. If it’s a thick one, give it a bit more time. This helps the steak soak back up all those good juices, making it way juicier.
Here’s a cool thing to try: next time, cook two steaks, slice one right away, and wait 5-10 minutes before cutting into another one. You’ll see what I mean: there’s a huge difference in how much juice stays in the steak.
Once your steak is done and sliced up, don’t forget to drizzle that butter from the pan over it. If the butter’s gone cold, give it a quick heat-up first. Then top it off with your fried garlic and herbs.
When’s the best time to take a flat iron steak off the pan?
Here’s a good example to explain it. I pulled my steak off the heat when it hit 111°F.
Then, in about 10 minutes, its temp shot up to 132°F. That’s a jump of 21°F! (Check out another photo below for this).
Many recipes say to take your steak off the heat 5, maybe 10°F before your target temp. But I’ve found that’s not always the best idea. If you take it off at 120°F, don’t be surprised if it ends up around 140°F inside! Of course, remember that all this mainly applies when cooking a steak in a pan at really high temperatures. When you’re using the reverse sear method to cook your steak, this issue doesn’t come up, or it’s barely noticeable.
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 doneness, around 135°F, you’ll want your steak to be at least 1.25 inches thick. Better yet, go for around 1.5 inches if you can. Here’s why: if your steak is too thin, it’ll cook through to the middle before the outside gets that nice, crispy crust. Check out the example below.
The steak on the left was cooked to 132°F, and the one on the right to 124°F. If you look at the photo, you’ll notice the right steak’s crust looks way better. That steak is thicker, so I had to cook it longer. I understand this isn’t the perfect comparison since you’d ideally cook 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, you’ll want to aim for medium-rare doneness for flat iron steak. But of course, everyone’s got a different preference. Some like the flat iron steak a bit more done, and that’s fine. Interestingly, even if you cook it more, it stays tender and juicy. So, this cut’s still a solid choice if you’re more into medium-well or well-done steaks.
What’s the best type of pan for searing a flat iron steak?
Technically, you can sear a steak in any old pan. But let’s be real, some pans are just better for this job. Take the beloved cast iron skillet, for example. It’s a champ at holding heat, exactly what you want when searing a steak. Not a fan of cast iron? No worries, stainless steel or carbon steel pans are great alternatives.
Pan-Seared Flat Iron Steak
- flat iron steak ideally, around 1.5 inches thick
- kosher salt
- black pepper finely ground
- butter unsalted
- 1 tablespoon High-smoke point oil I recommend refined avocado oil
- 1-2 garlic cloves
- thyme or rosemary fresh
- Prep Your Steak: Pat the steak dry and season with salt. For the best flavor, let it sit in the fridge for at least 45 minutes or overnight. If you're short on time, just salt it right before cooking.
- Preheat the Skillet: Heat the skillet over medium-high heat for 3-4 minutes then add about 2 teaspoons or 1 tablespoon of refined avocado oil.
- Season & Sear: Right before cooking, season the steak with pepper (and salt if you haven't already). Sear it in the hot skillet, flipping every 30 to 60 seconds, until it hits 100°F internally for a perfect medium-rare.
- Butter Basting: Toss in some butter along with garlic and herbs. Once the butter melts, baste your steak with this aromatic mixture, focusing on each side for about 30 to 45 seconds.
- Resting Time: Pull the steak off the heat when it's about 15-20°F away from your desired doneness. Let it rest for 5 to 10 minutes. This helps the juices redistribute, making your steak juicier.
- Serve it Up: Slice your steak and finish it with a spoonful of the herb-infused butter from the pan. Add the fried garlic and herbs on top for an extra flavor punch.
- Steak Thickness: Aim for a steak that’s at least 1.25 inches thick, especially if you like it medium-rare.
- Doneness Preference: While medium-rare is often the go-to for flat iron steak, feel free to adjust to your liking.
- Choosing a Pan: Cast iron is great for searing, but if you’re not a fan, stainless or carbon steel pans work well too.
- Watch your steak’s temperature closely. You’ll want to remove it from the heat a bit earlier than your target temp to avoid overcooking.