Cast Iron Flank Steak

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This Cast Iron Flank Steak includes an easy to prepare, deliciously flavorful marinade that ensures you get the most out of your steak. The cast iron produces a beautiful golden brown crust while leaving the inside juicy and tender. Perfectly paired with your favorite side and a salad, this steak is sure to be a win around the dinner table.
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Sliced flank steak on a serving platter.

Why you’ll love this recipe

  • Marinating beforehand makes the cast iron flank steak incredibly flavorful and tender.
  • Won’t break your pocketbook – flank steak is one of the most affordable cuts of red meat.  
  • Extremely easy recipe to follow and nearly impossible to mess up.  
  • High in protein and low in fat makes the cast iron flank steak a perfect dinner option.

What is Flank Steak?

Flank steak is a cut of meat from the rear abdomen of the cow. Being high in protein and low in fat makes it a nutritional powerhouse but also a tougher cut of meat, making the marinade for the cast iron flank steak crucial. Flank steak should be cut against the grain into thin strips, which help break up the muscle fibers and ensures you’ll get the most flavorful experience. 

Why I love cooking with flank steak.

I love cooking with this cut because it’s affordable but still yields delicious results when done correctly. I add it to fajitas, stews, stir fry’s and, of course, with a homemade marinade like the one in this cast iron flank steak. If you see a recipe call for beef strips, flank steak is your best option because of it’s ability to soak up flavors.

Sliced flank steak on a serving platter with cloth napkins.

Why a homemade marinade?

The homemade marinade is the way to go. It is cheaper and the end result is 1000 times more flavorful. This cast iron flank steak marinade was made in under 5 minutes and you likely have the ingredients on hand. Customizable to your liking and ensures you are getting the best quality without anything artificial makes taking the extra 5 minutes to make your own totally worth it!

Also, when it comes to marinating, the longer the better. Marinate for at least an hour. For a deeper and more intense flavor marinate for two hours or overnight.

Why a cast iron?

A good cast iron will last a lifetime and is a worthy investment for any kitchen. Virtually indestructible it becomes better with each use as the iron soaks up flavors, seasoning the pan in the process. Its ability to get extraordinarily hot ensures an even cook, resulting in a beautifully, “cooked to perfection” end result like in the cast iron flank steak. 

There are many cast irons to chose from. High end ones like, Le Creuset, have been around forever, are beautifully designed and live up to their reputation. But cast irons don’t have to break the bank. I use the Lodge cast iron and it works perfectly for a fraction of the cost.

How to use the cast iron.

A cast iron is great for foods that need a high heat for a short amount of time. The cast iron flank steak soaks the flavors of the marinade and when quickly seared on both sides, forms a crust to ensure those flavors stay in the meat. 

Once marinated, heat the cast iron over medium to medium high heat until it gets hot and the oil starts to shimmer and dance. This usually takes about 4-5 minutes. Do not to rush the heating process, you want the cast iron to be perfectly hot to get the sear. Once ready, carefully place the steak in the cast iron, take caution not to burn yourself with oil splatter. Cook for about two minutes on each side. When you see a golden brown crust it’s time to transfer the cast iron to the oven.

Ingredients and Substitutes:

These are the main ingredients and substitutions. See recipe card below for full ingredients list and instructions for cast iron flank steak. 

Steak: Try to find a flank steak that is equal thickness all around. The middle will always be slightly thicker, but the more uniform the steak, the more evenly it will cook. 

Coconut Aminos: Can be replaced with soy sauce.

Brown Sugar: Can be replaced by sugar substitute such as Swerve.

Worcestershire sauce: Use any you prefer.

Balsamic Vinegar: Gives the marinade a deep, rich flavor. Do not substitute. 

Herbs and SeasoningsDried rosemary and garlic go beautifully with this marinade and I don’t suggest substituting them.

Medium rare strips of flank steak on a serving platter.

How to make the cast iron flank steak:

Step 1: Prepare the marinade

In a small bowl, whisk together the olive oil, coconut aminos, minced garlic, brown sugar, Worcestershire sauce, balsamic vinegar, dried rosemary, salt, and black pepper to create the marinade.

Place the flank steak in a large resealable plastic bag or shallow dish. Pour the marinade over the steak, ensuring it is well-coated. Seal the bag or cover the dish and refrigerate for at least 1 hour, or up to 2 hours for a more intense flavor. Overnight is always best. 

Step 2: Prep

Preheat the oven to 400 degrees Fahrenheit. Remove the flank steak from the marinade, discarding the excess marinade, and let the steak rest at room temperature for 15 minutes before cooking. The discarded marinade has been accounted for in the nutrition facts.

Raw flank steak covered in marinade.

Step 3: Cook the steak

In a large cast iron skillet, heat the olive oil over medium-high heat until it begins to shimmer.

Carefully place the flank steak in the hot skillet and sear each side for 2 minutes or until a golden brown crust forms.

Transfer the cast iron skillet with the seared flank steak to the preheated oven. Cook the steak for 5-10 minutes, or until the internal temperature reaches your desired level of doneness (125°F / 51°C for medium-rare, 135°F / 57°C for medium). I recommend medium rare, which is about 5 minutes in the oven.

Flank steak being seared in a pan.

Step 4: Let rest

Remove the skillet from the oven and transfer the flank steak to a cutting board. Tent the steak with aluminum foil and let it rest for 5-10 minutes to allow the juices to redistribute.

After resting, slice the flank steak against the grain into thin strips.

Step 5: Eat!

Serve with your favorite sides and enjoy!

What to serve with this steak.

I love to add my oil free pesto to the top of the cast iron flank steak for a little extra flavor boost. For a more fruity and citrusy flavor, I suggest pairing with mango corn salsa. Roasted veggies,  garlic turmeric rice and Greek yogurt mashed potatoes are excellent sides to make this a complete meal. 

Medium rare strips of flank steak on a serving platter.

Nutritional Information Notes

This recipe makes approximately 4 servings at 4 oz. each. My steak weighed 1lb. 3 oz. and weighed 1lb. after cooked. 

If you like this recipe be sure to check out some of our other cast iron recipes!

Sliced flank steak on a serving platter.

Cast Iron Flank Steak

Danielle Lima
This Cast Iron Flank Steak includes an easy to prepare, deliciously flavorful marinade that ensures you get the most out of your steak. The cast iron produces a beautiful golden brown crust while leaving the inside juicy and tender. Perfectly paired with your favorite side and a salad, this steak is sure to be a win around the dinner table.
5 from 5 votes
Prep Time 10 minutes
Cook Time 15 minutes
Course Main Course
Cuisine American
Servings 4 servings
Calories 232 kcal

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Equipment

  • Cast Iron Skillet

Ingredients
  

  • 1 lb flank steak
  • 1 Tbsp olive oil
  • 1/4 cup coconut aminos 60g
  • 3 cloves garlic minced
  • 1 Tbsp brown sugar 13g
  • 1 Tbsp Worcestershire sauce
  • 1 Tbsp balsamic vinegar
  • 1 tsp. dried rosemary
  • salt and pepper, to taste
  • 1/2 Tbsp olive oil for cooking

Instructions
 

  • In a small bowl, whisk together the olive oil, coconut aminos, minced garlic, brown sugar, Worcestershire sauce, balsamic vinegar, dried rosemary, salt, and black pepper to create the marinade.
  • Place the flank steak in a large resealable plastic bag or shallow dish. Pour the marinade over the steak, ensuring that it is well-coated. Seal the bag or cover the dish and refrigerate for at least 1 hour, or up to 2 hours for a more intense flavor. Overnight is always best. 
  • Preheat the oven to 400 degrees Fahrenheit. Remove the flank steak from the marinade, discarding the excess marinade, and let the steak rest at room temperature for about 15 minutes before cooking. The discarded marinade has been accounted for in the nutrition facts.
  • In a large cast iron skillet, heat the olive oil over medium-high heat until it begins to shimmer. Carefully place the flank steak in the hot skillet and sear each side for 2 minutes, or until a golden brown crust forms.
  • Transfer the cast iron skillet with the seared flank steak to the preheated oven. Cook the steak for 5-10 minutes, or until the internal temperature reaches your desired level of doneness (125°F / 51°C for medium-rare, 135°F / 57°C for medium). I recommend medium rare, which is about 5 minutes in the oven.
  • Remove the skillet from the oven and transfer the flank steak to a cutting board. Tent the steak with aluminum foil and let it rest for 5-10 minutes to allow the juices to redistribute.
  • After resting, slice the cast iron flank steak against the grain into thin strips.

Notes

  • Makes 4 servings at 4 oz. cooked steak each.
  • Marinate for at least an hour – overnight is always best.
  • The discarded marinade is reflected in the nutritional information.
  • Be careful not to overcook. Flank steak will become tough if cooked too long.

Nutrition

Serving: 4ozCalories: 232kcalCarbohydrates: 3gProtein: 24gFat: 13gSaturated Fat: 5gPolyunsaturated Fat: 2gMonounsaturated Fat: 2gCholesterol: 75mgSodium: 185mgPotassium: 36mgSugar: 3g
Tried this recipe?Let us know how it was!

6 Comments

  1. 5 stars
    This was so delicious! I highly recommend. Easy to make. I have found that while on my macros journey, the lower fat meat can lack in flavor, but this marinade more than made up for it!

    I did use with a top sirloin as my store didn’t have flank steak, and we grilled as I don’t have a cast iron pan. Quite tasty!

    1. I couldn’t agree more about the marinade. Also, good to know the sirloin came out so well. I’ll have to try that if I ever can’t get flank.

  2. 5 stars
    Tried this recipe to make fajitas on Cinco De Mayo and was a huge hit with the family & perfect to stay within my macros!

  3. 5 stars
    Made this for dinner yesterday (though my grocery store didn’t have flank steak so I substituted a flat iron… I know that will change the macros a bit, but it was the closest I could get to the called for cut of meat)! It was DELICIOUS! I also made the pesto that was recommended to go with it and that was a great flavor combination! Already can’t wait to make this one again! (Side note – I am fairly new to the world of cast iron. Any tips or tricks you have for using it/cleaning it/seasoning it I’m all ears! I follow what internet searches tell me to do but I still struggle to keep a nonstick surface to it lol. At least it cooked this steak up great!)

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