Marinated Grilled Flank Steak Sandwiches

I admit, I’m way too excited to try this easy dinner. It looks SO GOOD. We’re hosting a little graduation gathering this weekend and I think these Grilled Flank Steak Sandwiches will be perfect. In fact, I can easily predict we’ll be making these sandwiches all summer long. And don’t miss the White Cheddar Spread recipe that Lindsey came up with too (she included it below). So mouth watering. I might need to make this tonight, just to “test” it for the weekend. : )

Marinated Grilled Flank Steak SandwichesMarinated Grilled Flank Steak SandwichesMarinated Grilled Flank Steak Sandwiches

Here’s what Lindsey says:

Summer is almost here! That means BBQ season, beach trips, popsicles and lemonade, ice cream, long days and short nights. Summer! While dusting off the grill to barbecue burgers may seem like the perfect way to usher in summer, I implore you to give these grilled flank steak sandwiches a try as a burger alternative.

Marinated Grilled Flank Steak Sandwiches

Flank steak is a flavorful lean cut of beef that comes from the abdominal area of a cow. With long fibers running down the length, it’s important to take care when preparing this particular cut to keep it from being dry and tough. Flank steak benefits from time spent marinating, and quick cooking like grilling. (This isn’t one that you’d toss into the oven or slow cooker!)

Once cooked, flank steak should be thinly sliced against the grain for maximum tenderness. When done right, flank steak is as flavorful and melt-in-your-mouth as more expensive cuts. If you haven’t tried flank steak yet, I think you’ll really love it. Even if you have, still give this marinade a try. It’s so, so good. (More on that in a second.) And if you can’t find flank steak, or prefer a different cut, flat iron, hangar, or skirt steaks are great substitutes in this recipe.

Marinated Grilled Flank Steak Sandwiches

The BEST marinade I have ever used is one I found on Epicurious about ten years ago. It may seem like a strange mix of ingredients, but it is incredible. I’ve made some slight tweaks to the original recipe over the years and it still remains one of our very favorite marinades for beef and chicken. So if you’re not a fan of meat or just prefer chicken, know that you can totally make this meal with chicken breasts or thighs.

Marinated Grilled Flank Steak Sandwiches

Flank steak doesn’t need much time on the grill. Four to five minutes per side, depending on the thickness, will yield a medium-rare steak. I’ve found that direct heat is the best  grilling method. It sears in all of those tasty juices, and because flank steak isn’t too thick, the quick, super-high heat is perfect.

After grilling, it’s important for the meat to rest, off the heat and covered with foil, to allow the juices to be reabsorbed into the meat. There is usually a narrower, thinner end to the flank steak that cooks much more quickly than the rest of the meat. I kind of like that because we have people in our family who like everything from rare to more well-done. But be careful not to overcook flank steak; it is better and at its most tender in the medium to medium-rare range.

Marinated Grilled Flank Steak Sandwiches

The flank steak, once marinated and cooked, is certainly flavorful enough on its own — but I’m never one to leave things simple! I have to go that extra mile. My husband and I were debating whether or not these sandwiches really needed cheese. I was thinking provolone. He was saying “no cheese,” which is unusual for him. And then an idea came to me — a white cheddar spread.

Grilled Flank Steak Sandwiches with Cheddar Horseradish Spread

I did a little looking around based on the idea I was formulating and found several really good recipes that I drew from to create this delectable White Cheddar Horseradish Spread. Oh my goodness, it’s so good! One recipe makes more than enough for the sandwiches, so I highly recommend finishing off the leftovers as a veggie dip or with crackers.

Horseradish is a classic accompaniment to meat and the grainy mustard pumps up the flavor. I added a little dried dill, too, though I suspect it would be just fine without it or with another herb in its place. I’m not a fan of mayo, so this spread uses sour cream. Like I said: so good!

Marinated Grilled Flank Steak Sandwiches

As far as the other sandwich fixings go, I’m partial to arugula and other non-lettuce greens for a sandwich like this. But totally go with lettuce if that’s your preference. Whatever you do, find the juiciest, sweetest heirloom tomatoes and cut them into thick slices. You won’t be sorry. (I’ll get to those onions in a minute…)

Marinated Grilled Flank Steak SandwichesMarinated Grilled Flank Steak Sandwiches

I think an often overlooked secret to a good burger (or flank steak sandwich) is the bun. There are a lot more options out there now than there used to be. I reach for brioche buns. They are lightly sweet and sport a pretty, burnished top. They’re sturdy enough for spreads and sauces, and all manner of toppings. And they really are perfect here. Grilling the buns is an extra, optional step, but well worth it.

Marinated Grilled Flank Steak Sandwiches

And I would be remiss if I didn’t mention my love for grilled onions. Sigh. If you’ve already got the grill piping hot, it’s a no-brainer to cook the onions on the grill too. I opt for a cast-iron skillet because it can handle the high heat, but any grill-safe pan works fine too. I cook them in straight up butter with a tiny bit of a high-heat oil to keep the butter from burning. It takes a good 20-25 minutes for the onions to cook to golden perfection, but luckily enough, that’s just about the right amount of time the flank steak needs to rest after grilling.

Marinated Grilled Flank Steak Sandwiches

The flank steaks I buy tend to come in 1.5 pound pieces. That should feed 4-6 people nicely. For a bigger crowd, it’s easy enough to toss a few extra steaks into the marinade. I know these would be a huge hit at your next BBQ party.

Marinated Grilled Flank Steak Sandwiches

Marinated Grilled Flank Steak Sandwiches

1 (1.5 to 2 lb.) flank steak
Sea salt

For marinade:
1/3 cup olive oil
1/4 cup balsamic vinegar
1/4 cup fresh lemon juice
2 tablespoons Dijon mustard
2 tablespoons soy sauce
1 1/2 tablespoons Worcestershire sauce
1 tablespoon honey or maple syrup
4 garlic cloves, minced
1 teaspoon each: dried oregano, basil, thyme
1/2 teaspoon freshly ground black pepper

For sandwiches:
White Cheddar Horseradish Spread (see notes for recipe)
1 extra large red onion, thinly sliced (see notes)
2 large ripe tomatoes, thickly sliced
2 cups baby arugula or tender lettuce leaves
6 brioche buns, halved and toasted or grilled, if desired

1. Prepare marinade by whisking together all of the ingredients. Place the flank steak in a shallow casserole dish or resealable plastic bag and pour the marinade over the top. Allow to marinate in refrigerator for 2-3 hours, minimum, preferably 5-6 hours, or overnight. Remove flank steak from marinade and allow to come to room temperature, about 30 minutes.
2. Preheat barbecue grill (or stovetop grill pan) for direct heat. Clean and lightly oil grill grates. Season the steak on both sides with a little sea salt. Place flank steak directly over the hot coals or flame and cook for 4-5 minutes on the first side, and another 4-5 minutes on the other side. This should yield a medium to medium-rare steak depending on the thickness. Cook for a few minutes longer, to preferred doneness, if desired.
3. Place steak on a cutting board or platter. Cover with foil and allow to rest for 15-20 minutes to allow juices to be reabsorbed into the meat.
4. Using a sharp knife, cut meat into very thin slices, going against the grain.
5. To serve, place on buns with desired toppings and serve warm.

Yield: 4-6 servings

– Other cuts of meat such as flat iron, hangar, or skirt steak can be substituted for the flank steak.
– 2 pounds of chicken can be substituted for the steak. Marinate and grill as directed, making sure chicken reaches an internal temperature of 160°F.

Marinated Grilled Flank Steak Sandwiches

White Cheddar Horseradish Spread

8 ounces extra sharp white cheddar, grated
1/2 cup sour cream or mayonnaise
1-2 tablespoons prepared horseradish, drained, to taste
1 tablespoon grainy or Dijon mustard
1/2 teaspoon dried dill (optional)
Sea salt and freshly ground black pepper, to taste

1. Place all of the ingredients into a food processor fitted with the chopping blade. Pulse until the cheese is finely chopped and the mixture is thick and creamy. Taste and add sea salt and black pepper, if needed.
2. Transfer to a container with tight-fitting lid and store in refrigerator for up to 1 week.

Yield: about 1 1/2 cups

Marinated Grilled Flank Steak Sandwiches

Grilled Onions

1 extra large red onion, cut into 1/8-inch thick rounds
2 tablespoons salted butter
1 tablespoon high-heat oil, such as avocado

1. Have a grill-safe pan ready, such as a cast-iron skillet. Add butter and oil to the pan. Place pan over direct heat. When butter is bubbling and hot, add the onions. Toss with long handled tongs to coat the onions with the butter. Let cook, tossing occasionally, until onions are tender and deep golden on the edges, about 20-25 minutes.
2. Transfer to a bowl and keep warm until ready to serve.

Marinated Grilled Flank Steak Sandwiches
Marinated Grilled Flank Steak Sandwiches


Oh my goodness. Thank you, Lindsey! I am unreasonably happy about this recipe. It looks like the ideal warm weather dinner to me. And I’ve never tried flank stead on the grill — so I’m look-forwarding to learning this new cooking skill.

What about you, Dear Readers? Will you be grilling this summer? Have you ever used your cast-iron pan on the grill? This will be my first time. 

P.S. — More easy dinners. And how to grill the perfect burger.


Credits: Photos and recipes by Lindsey Rose Johnson for Design Mom.