Grilled Flat Iron Steak (with Creamy Peruvian Green Sauce)
Updated Jan 10, 2025
A juicy, flavourful Flat Iron Steak recipe for the grill that turns out perfect every time. Learn how to cook it like a pro with my best tips.
What is Flat Iron Steak?
Flat iron steak is a cut of beef that comes from the shoulder (chuck) of the cow. Though it’s from a tougher area, it’s known for being tender due to the removal of connective tissue.
It has good marbling, which makes it flavorful. It’s versatile and great for grilling, pan-searing, or broiling. Its beefy flavor is similar to ribeye but more affordable.
I like to cook it over high heat and slice it thinly against the grain for extra tenderness. It’s an underrated cut that delivers on flavor.
Flat iron steak is the second most tender cut after filet mignon. Its tenderness and rich flavor make it a great choice for those who want a balance of taste and value.
Here’s What You Need
I keep this easy Flat Iron Steak recipe super simple, then serve it with my favorite flavor-packed green sauce for steak, called Aji Verde. Round up the ingredients and tools so you can get cooking!
Flat Iron Steak Recipe Ingredients
- Flat Iron Steak: See possible substitutes below.
- Cooking oil: Choose an oil with a high smoke point for achieving a good sear without burning. I like avocado oil and olive oil (not extra virgin). Canola or vegetable oil work, too.
- Coarse salt and black pepper: Kosher salt and freshly cracked pepper enhance the natural flavors of the meat. They also help develop a delicious crust when seared.
Substitutes for Flat Iron Steak
If you can’t find flat iron steak, here are some good substitutes:
- Hanger steak: Similar in tenderness and flavor, but with a slightly more pronounced beefy taste.
- Skirt steak: A bit chewier, but great for grilling and quick cooking.
- Flank steak: Leaner and slightly tougher, but works well when sliced thin against the grain.
- Ribeye: More expensive but has a similar rich flavor and tenderness.
Each of these can be cooked similarly, but adjust cooking times depending on thickness and desired doneness.
Tools Needed
You don’t much to make this yummy steak recipe with its tasty sauce!
- Gas or charcoal grill, or grill pan. A shining hot skillet works beautifully, too.
- A brush to coat the steak with oil and a small bowl to hold the oil.
- Cutting board and knives.
How to Make Flat Iron Steak Recipe: An Easy Guide
Here is exactly how I make this recipe at home, step-by-step:
Prepare the sauce
Combine all the ingredients in a small food processor or blender. Pulse until the mixture is relatively smooth but still has some texture.
Prepare the steak
Brush both sides of the steak with a teaspoon at a time of oil and generously season with salt and pepper.
Grill the steak
Place the steak on the preheated grill and allow it to sear on one side without moving it. Wait until it easily lifts when you gently raise a corner with tongs.
Here’s my guide to the best temperature for grilling steak.
Once the first side has nice grill marks and is well-seared, flip the steak and continue cooking until it reaches an internal temperature of 125ºF for medium-rare.
Rest and serve
Transfer the steak to a cutting board and cover it loosely with foil. Let it rest for 5 minutes to allow the juices to redistribute. Slice the steak and drizzle the green sauce over the top before serving.
Internal Temperature for Flat Iron Steak Doneness
Here are the internal temperatures for different levels of doneness for flat iron steak:
Rare: 120-125°F
Medium-rare: 130-135°F
Medium: 140-145°F
Medium-well: 150-155°F
Well-done: 160°F+
For best results, remove the steak from heat when it’s about 5°F lower than your target temperature. It will continue cooking from residual heat (carryover cooking) as it rests.
5 Common Mistakes When Making a Flat Iron Steak Recipe
This is often where folks fall down when making this recipe. Here’s what to avoid:
- Overcooking: Cooking beyond medium-rare leads to toughness. Aim for an internal temperature of 125ºF which you can test with an instant-read thermometer.
- Skipping the rest: Not letting the steak rest causes juices to run out. Always rest for at least 5 minutes.
- Under-seasoning: Insufficient seasoning results in bland flavor. Season generously with salt and pepper.
- Cold grill or pan: Cooking on a cold surface prevents proper browning. Preheat your grill or pan for 5-10 minutes. Your surface should be shimmering hot and not at a medium-high heat.
- Cutting with the grain: Slicing in the same direction as the grain makes the steak tough. Always cut against the grain for tenderness.
Make Ahead and Storage
Cooked flat iron steak can be stored in the fridge for up to 3 days.
To reheat, gently warm it in a skillet over low heat to avoid overcooking. Always store leftovers in an airtight container to maintain freshness.
You can freeze leftover steak and thaw to use it in sandwiches etc.
READ MORE: How to Defrost Steak in the Microwave.
How to Serve this Flat Iron Steak Recipe
Serve this simple flat iron steak recipe with a yummy sauce! Here are some of my favs:
- Peruvian aji verde – the creamy green sauce pictured (recipe below!)
- Garlic Butter Sauce – a classic for a reason.
- Chimichurri Sauce (green sauce for steak) with fresh herbs and a bright zing
Flat Iron Steak Side Dishes
- Try it with creamy mashed potatoes, cornbread casserole, or air fryer eggplant.
- It’s also lovely with crunchy green veggies like beans and pan-fried asparagus.
If you have any leftover steak, slice it thinly for use in sandwiches, salads, or turn it into a version of beef tacos. Here’s the best way to reheat leftover steak.
Final Notes, Pro Tips + Science-Based Secrets
As a food scientist, I love to share my tips and tricks to getting incredible results:
- Patience on the grill: Resist the urge to flip the steak too soon. Allowing it to sear properly before flipping creates a flavorful crust, enhancing both texture and taste.
- Consider marinating: Make up your favorite marinade and smother your steak in it to rest overnight in.
- Use a meat thermometer: To achieve perfect doneness, use a meat thermometer. This ensures you hit the ideal temperature without guessing, preventing overcooking.
- Resting is key: Allow the steak to rest after cooking. This is crucial for redistributing the juices throughout the meat, resulting in a juicier, more flavorful steak when sliced.
- Cutting technique: Always slice against the grain to maximize tenderness. This shortens the muscle fibers, making each bite easier to chew.
FAQs About Flat Iron Steak Recipe
Just skimming through? Here are a few highlights:
Yes, flat iron steak is known for its tenderness, making it a popular choice for grilling and pan-searing.
Yes, flat iron steak can be eaten rare; however, it’s best enjoyed medium-rare for optimal flavor and tenderness.
Yes, flat iron steak is generally more tender than sirloin due to its fine grain and marbling, which contribute to its juiciness and flavor.
For medium-rare, aim for an internal temperature of 125ºF. Use a meat thermometer to check the temperature, inserting it into the thickest part of the steak.
Yes! While flat iron steak is what this recipe has in mind, you can substitute it with other cuts like flank steak, skirt steak, top blade steak, or ribeye, though cooking times and techniques may vary.
You can make flat iron steak more tender if you marinate it with something acidic (like balsamic vinegar or lemon juice), but allowing the steak to rest after cooking is also key. This helps redistribute the juices, resulting in a more tender texture. Slicing against the grain also enhances tenderness.
Other Steak Recipes You’ll Love
Here are some more steak recipe picks to try out.
- Make beef steak broccoli stir-fry when you’re in the mood for a tossed-together kinda meal.
- This recipe for steak made in an Instant Pot delivers butter-tender beef that you can (almost) eat with a spoon!
- My Salisbury steak is dripping in rich flavors and goodness.
- Steak benny with blue cheese and buttermilk Hollandaise? Yes, please!
Easy Flat Iron Steak Recipe (with Creamy Peruvian Green Sauce!)
Ingredients
For Steak
- 1 lb flat iron steak
- 1 tbsp vegetable oil
- 1 tsp kosher salt
- ¼ tsp black pepper
For Sauce
- ½ cup fresh cilantro
- ½ cup fresh parsley
- 3 medium cloves garlic
- 2 small green chilies (or 1 jalapeno)
- ½ lime, juiced
- ¾ tsp coarse salt
- ¼ cup olive oil
- ⅓ cup mayonnaise
Instructions
Grill the Flank Steak
- Preheat grill or grill pan over high heat for 5-10 minutes. Brush steak on both sides with oil. Sprinkle generously with salt and pepper. Grill steak over direct heat until well seared on bottom. Don't attempt to flip it until it releases easily when you gently lift a corner with tongs. When the bottom is nicely seared with beautiful grill marks, flip and finish cooking on the other side until internal temperature reaches 125ºF for medium rare.
Make Creamy Peruvian Green Sauce
- Add all ingredients to a small food processor or blender. Pulse until mixture is fairly smooth but not pureed.
Rest + Serve
- Transfer steak to a cutting board, tent with foil and let it rest for 5 minutes to redistribute the juices before slicing. Serve steak sliced with green sauce drizzled over.
Notes
- While grilling is recommended for a delicious char, you can also use a cast-iron skillet for excellent results. Just ensure it’s preheated for a good sear.
- Season the steak well for the best flavor results.
- Don’t skip the resting period after cooking. Letting the steak rest for at least 5 minutes allows the juices to redistribute, ensuring a juicy bite.
- Hanger steak: Similar in tenderness and flavor, but with a slightly more pronounced beefy taste.
- Skirt steak: A bit chewier, but great for grilling and quick cooking.
- Flank steak: Leaner and slightly tougher, but works well when sliced thin against the grain.
- Ribeye: More expensive but has a similar rich flavor and tenderness.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
This recipe is such a hidden gem I stumbled upon it by chance and now I’m completely hooked!
The sauce was excellent! Had it last night over thin cut strip loin. Flat Iron steak wasn’t available anywhere I looked (grocery and two butchers). Thank you this recipe!!!