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Grilled Flank Steak with Mushrooms is a delicious and flavorful recipe that you’re going to love. With marinated beef, Baby Bella mushrooms, fresh herbs, and lemon, it’s a savory, satisfying dinner that is perfect for a date night in or for a family dinner!

If you love grilling then you’re going to love these other fantastic grill recipes! Check out how to make Grilled Ribeye Steak or the PERFECT Juicy Grilled Turkey Burgers. Of course, save some room for dessert because Grilled Peaches with Ice Cream makes a fabulous treat to follow up this steak and mushrooms dinner!

A skillet of sliced flank steak and mushrooms next to roasted asparagus.

Flank steak is a fantastic cut of meat that takes really well to marinades and quick grilling. The real trick to understanding this cut of meat is to know where the grain is and slice it thinly against the grain (i.e., perpendicular to the lines you see running through the flank steak). If you can master that simple skill, you are well on your way to tender, flavorful flank steak!

Grilled Steak and Mushrooms

I think every steakhouse I have ever gone to has some steak and mushroom combination on the menu. And there is a good reason for it: steak and mushrooms are a fabulous combination both in terms of flavor and textures. A properly cooked steak with tender mushrooms can melt in your mouth and leave you reaching for another bite.

This grilled flank steak is delicious even without the mushrooms, if you happen to have a fungi hater in your family. But putting them together is pure magic.

This recipe is very easy and doesn’t take much hands-on time at all. Aside from a marinating period for the meat, the rest of this dish could be made in under 30 minutes, making it perfect for a nice dinner after a busy day.

Medium-rare strips of grilled flank steak.

Ingredients needed for Grilled Steak and Mushrooms

Don’t let the long ingredient list overwhelm or intimidate you. It’s almost all stuff you already have on hand in your pantry and the marinade can be thrown together in about a minute.

For the marinade we will need:

  • Soy sauce
  • Balsamic vinegar
  • Olive oil
  • Minced garlic
  • Ground ginger
  • Black pepper
  • Salt
  • Lemon juice

For the steak and mushrooms we will need:

  • Flank steak
  • Baby bella mushrooms
  • Butter
  • Minced garlic
  • Olive oil
  • Salt and pepper
  • Fresh rosemary
  • Beef broth
  • Cornstarch
Ingredients for a flank steak marinade.

Pro Tip: This marinade also works well with other cuts of beef like skirt steak, ribeye, and New York strip. I just particularly like it with flank steak.

How to Make Grilled Flank Steak and Mushrooms

  1. Marinade the steak: In a large reusable silicon bag or glass bowl, combine the marinade ingredients and then add the flank steak, turning to coat and submerging as much as possible. Let it marinate in the fridge for a minimum of 2 hours, but no more than 24 hours. I find I get better penetration of the marinade by poking the flank steak all over with the tines of a fork first.
  1. Grill your flank steak: Prepare your grill by setting it to high heat and then cook your flank steak for roughly 6 minutes on each side until it’s the temperature and level of doneness that you desire.
  2. Rest the meat: Let your flank steak rest for 10 minutes after cooking it so that the juices can be reabsorbed into the meat and won’t drain out all over the place. This keeps your meat juicy and delicious and is well worth the wait! Then thinly slice your meat across the grain.
  3. Make a slurry for the mushroom sauce: In a small bowl, combine the cornstarch and 2 tablespoons of beef broth to make a slurry, set it aside.
  4. Cook the mushrooms: In a hot, dry pan, sear the mushrooms for 2-3 minutes. Season with salt and pepper, then add in butter, minced garlic, fresh rosemary, and olive oil.
  5. Add broth: Pour in beef broth and let the mixture cook for an additional 3-4 minutes. Stir in the cornstarch slurry and cook until slightly thickened and silky, then remove from the heat.
  1. Serve: Serve your cooked mushrooms alongside or overtop your cooked and thinly sliced flank steak. Enjoy!

Do you have to marinate flank steak?

Flank steak by nature is a rather lean and tough piece of meat on its own. It comes from the underside of a cow so it’s very well-worked and flavorful, but marinating and grilling it is a great way to get the best taste and texture out of it.

While you don’t absolutely have to marinate flank steak before cooking, it is something that I highly recommend if you want to enjoy a tender and flavorful steak. The marinade that I share in this recipe helps to tenderize the meat and add a lot of flavors that pair really well with the cooked mushrooms.

How long does it take to grill a flank steak?

Depending on the size of the cut and how done you want the steak to be before enjoying it, the time can vary. A general rule of thumb is about 5-6 minutes per side or until it reaches a minimum of 120F degrees.

  • 120-125 degrees F is rare
  • 130-140 degrees F is medium rare
  • and the higher the temperature the more cooked your steak will be.
Sliced flank steak and mushrooms in a cast iron skillet.

Can you over marinate beef?

Yes! Marinades shouldn’t go on for much longer than recommended by the author of any recipe because overdoing it will cause the fibers to break down too much and make the meat mushy.

How to cut flank steak

When you look at a piece of meat you will notice a grain that runs in a single direction along the top and bottom pieces. You always want to cut against it, meaning that if the grain runs the longways of the steak, you cut slices going short ways, crossing right over the grains.

What this does is cuts the fibers in the meat, thereby making it more tender to chew and saving your teeth (and jaw) a lot of added work! We want this flank steak to be cut into thin strips going across the grain so that every bite is as tender as possible.

Flank steak sliced against the grain on a cutting board.

What to serve with flank steak

Looking for some great side dish ideas to go along with this dish? I highly recommend some of these!

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Grilled Flank Steak with Mushrooms
Yield: 6-8 servings

Grilled Flank Steak with Mushrooms

Grilled Flank Steak with Mushrooms is a delicious and flavorful recipe that you're going to love. With marinated beef, Baby Bella mushrooms, fresh herbs, and lemon, it's a savory, satisfying dinner that is perfect for a date night in or for a family dinner!

Prep Time 15 minutes
Cook Time 20 minutes
Additional Time 2 hours
Total Time 2 hours 35 minutes

Ingredients

Marinade

  • 1/3 cup soy sauce
  • 2 tablespoons balsamic vinegar
  • 1/4 cup olive oil
  • 4 cloves minced garlic
  • 1 teaspoon ground ginger
  • 1 teaspoon black pepper
  • 1/2 teaspoon salt
  • Juice of 1 lemon (about 1/4 cup)

Steak & Mushrooms

  • 1 flank steak (about 1 1/2 to 2 pounds)
  • 16 ounces baby bella mushrooms, cut in half or quarters if large
  • 2 tablespoons butter
  • 2 cloves minced garlic
  • 1 tablespoon olive oil
  • Salt and pepper
  • 1 tablespoon fresh rosemary, chopped
  • 1 cup beef broth, divided
  • 1 teaspoon cornstarch

Instructions

  1. Combine marinade ingredients. Marinate at least 2 and up to 24 hours.
  2. Grill over high heat for 6 minutes per side until 120-125 degrees for rare and 130-140 degrees for medium-rare.
  3. Let it rest for 10 minutes before thinly slicing against the grain.
  4. Combine 2 tablespoons beef broth with cornstarch to make a slurry.
  5. Add mushrooms to a hot dry pan and cook 2-3 minutes. Season with salt and pepper.
  6. Add butter, garlic, rosemary, and olive oil.
  7. Add broth and cook 3-4 minutes.
  8. Add slurry, cook until slightly thickened.
  9. Slice meat against grain and serve with mushrooms.

Nutrition Information:

Yield:

6

Serving Size:

1

Amount Per Serving: Calories: 207Total Fat: 17gSaturated Fat: 5gTrans Fat: 0gUnsaturated Fat: 11gCholesterol: 21mgSodium: 1187mgCarbohydrates: 8gFiber: 2gSugar: 3gProtein: 8g