Marinated and grilled flank steak is a simple, yet incredibly flavorful way to prepare a flank steak! The rosemary balsamic marinade is the perfect blend of savory with just a touch of sweet that is all highlighted in the flank steak by that char from the grill.
Flank Steak Marinade
The key to any great marinade is including these 5 key elements- salt, sugar, acidity, oil, and seasonings. The salt and sugar help season the meat as well as increase the tenderness and juiciness of the meat. The acidity adds that tangy bite and the oil helps to transfer all of that marinade into the meat itself. Finally, the seasonings are there to really influence the overall flavor profile of the meat.
This marinade covers all of those bases with balsamic dressing for acidity, olive oil, salt, a little hit of sugar, and plenty of flavor from the rosemary, garlic, and black pepper. It really is the perfect balance of flavors that also helps tenderize the flank steak while it marinates. I recommend marinating for at least 2 hours, but this marinade is so balanced, you can push it up to 24 hours for maximum flavor and tenderness.
How to Cook Flank Steak
Flank steak is a thin cut of beef that sits along the belly of the cow. The muscle grain all runs in a single direction, so the flank steak is ideal for marinating and grilling. I like to marinate to help tenderize and flavor the flank steak, and then sear over a really hot grill until medium rare.
Since the flank steak is so thin, it grills up incredibly quickly. I like to get my grill preheated to at least 450 degrees F so that when the steak hits the grill grates, you get a nice crispy sear on the outside. I typically grill for 4-5 minutes per side, but the most important thing is internal temperature.
Temperature for Flank Steak
Use an instant read thermometer (I love this digital version for $29) to monitor the steak as it is grilling. Cook to 125 degrees F for a Rare steak, 135 degrees F for Medium Rare, or 145 degrees F for Medium. Flank steak is lean and tends to dry out when cooked above medium, but if you must, 155 degrees F is Medium Well, and 165 degrees F is Well Done.
Grilled Flank Steak Recipe
- 1 1.5-2 pound flank steak
- 1/2 cup olive oil
- 1 1/2 teaspoons Kosher salt
- 1 1/2 teaspoons black pepper
- 1/4 cup brown sugar
- 2 Tablespoons Worcestershire sauce
- 1/4 cup balsamic vinegar
- 5 cloves garlic minced
- 1 teaspoon crushed red pepper flakes
- 2-3 sprigs fresh rosemary
In a gallon zip top bag, combine all of the ingredients for the rosemary balsamic marinade. Zip the top, then toss gently until all of the salt and sugar granules are dissolved.
Place the flank steak in the marinade, press out any excess air from the bag, and seal tightly. Using your hands, massage the marinade around the meat. Refrigerate for at least 2 hours, or up to 24 hours.
Preheat your grill for direct heat grilling at 450 degrees F. Grill the steak for 4-5 minutes per side, or until an internal thermometer reads 130-135 degrees F for medium rare. Remove the steak from the grill to a cutting board and allow to rest for 10-15 minutes.
Slice the steak into thin strips against the grain (perpendicular to the long strands of muscle) and enjoy!