Flat Iron Steak on a Pellet Grill

Grilled flat iron steak on a cutting board with a slicing knife

This is one of my favorite steak recipes and is always a crowd pleaser. This marinade is great way to add a unique flavor before cooking to perfection on your pellet grill.  You can use it with any cut of beef, like a flank steak, London broil, or skirt steak.  It is super simple to make and will absolutely wow your family and friends.  In the recipe below I will describe a few of my tips and tricks to help you make the best steak of your life.

Ingredients

This marinade only contains 6 ingredients. The marinade helps to tenderize the meat and introduces amazing flavor into the steak from the fresh rosemary, garlic, and honey. The trick is to not OVER-marinate your steak.   This marinade contains soy sauce so it can easily over-salt your steak if you let it marinate for too long. That means no more than 8 hours.  If I am cooking at 5PM I will typically start the marinade at 8am or 9am.

  • 1/2 cup olive oil

  • 1/2 cup soy sauce

  • 6 cloves fresh garlic – chopped

  • 4 tablespoons fresh rosemary diced (fresh rosemary is necessary!, don’t cheat with the dried stuff)

  • 6 tablespoons of honey

  • 1 tablespoon fresh ground black pepper

Cutting board with steak marinade ingredients including garlic, rosemary, soy sauce, olive oil, honey, and pepper.

How to Marinate Steak

Marinating steak is a great way to prepare your steak before grilling to add more flavor. Once you have all your ingredients assembled, it is important to marinate your steak in right container. I use a gallon sized ziplock freezer bag because it allows me to press out all the air, and I can ensure that the marinade is coating all sides of the steak. You can also use a small bowl to marinate the steak but you will need to turn the steaks a few times while marinating.

Place your steak and all ingredients of marinade in a large ziplock bag. Massage the meat in the marinade to ensure it is evenly coated on all sides. Place the marinating steak in the refrigerator and allow the steak to marinate for 4-8 hours.

Quick note: This marinade is good for one steak up to approximately 1.5 pounds. If you are grilling more than one steak, you will need to double or triple the recipe.

Instructions

Measure the extra virgin olive oil and soy sauce and place it in a glass bowl.  

Peel and chop 6 cloves of fresh garlic.

Peel the leaves of rosemary off the wooden stalk. Dice the rosemary

Preparing to chop garlic and rosemary on a cutting board.

Place the chopped garlic, rosemary, and pepper in the bowl with the oil and soy sauce.

A bowl with garlic, rosemary, and pepper for a steak marinade.

Add four tablespoons of honey to the bowl of ingredients

Whisk the marinade until the honey is dissolved into the oil and soy sauce.

A bowl of steak marinade mixed

Place your steak in a gallon-sized ziplock bag.

Pour the marinade to the bag and let it sit in the refrigerator for 4-8 hours.  

A flat iron steak in a ziplock bag that contains steak marinade.

Take the steak out of the refrigerator about an hour before you are ready to cook so the fibers in the steak are able to relax (trust me, once you try this you will do it every time!)

Preheat your pellet grill to 500 degrees and let it warm up for minimum of 25 mintures

A marinaded steak on a pellet grill

Place your steak on the grill and grill for 5 minutes each side. Check the internal temperature with an instant read thermometer to ensure the steak is cooked to your desired doneness. Typically I like to serve flat iron steak at medium rare. If I am cooking a flank steak I find that medium is a better temperature. But it is up to you and your preference. Remember you steak will continue to cook when you take it off the grill and the internal temperature will rise 3-5 degrees while it rests.

A flat iron steak grilled on a pellet grilled

After your steak is cooked, take it off the grill and let it rest on a place for 10 minutes before slicing. This lets the muscle fibers relax and the juices to distribute evenly back throughout the entire cut of meat.

Slice across the grain and ENJOY!

How Long Should I Marinate Steak?

I recommend marinating steak for around 4 hours to 8 hours to allow all the flavor penetrate the meat well. I generally avoid marinating steaks longer than 8 hours. Marinating more than 8 hours can make the meat turn mealy and dry.

A general rule is if you have thinner cuts of steak, marinate them for a shorter amount of time. Thinner steaks like a flank steak or flat iron can marinate for at least 3-4 hours for great flavor. For thicker steaks, like a London broil, I recommend 4-8 hours. The longer your steak sits in the marinade, the stronger the flavor becomes. If you over marinate steak you run the risk of eating a dry and overly salted piece of meat.

Enjoy!

I usually only season steak with salt and pepper. However this flavorful marinade is absolutely delicious and is one of my family’s favorites. Give it a a try, the unique soy sauce and rosemary combination will soon be your favorite too!

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