The marinated flank steak sandwich with a rich umami flavor from the thinly stacked steak topped with pickled red onion and smothered with chimichurri aioli. The fresh blast from the herbed aioli and the juicy steak melt in your mouth. This will be a sandwich put on repeat!
Why this Recipe Works
This steak chimichurri sandwich has the brightest and freshest ingredients that make this a decadent delight. The generous smear of chimichurri aioli is a creamy topping that has a slightly spicy kick with the addition of fresh jalapeno.
Weeknight Ready – This is a versatile recipe that can be made on those weeknights when the hours are few or on a weekend when you host friends and family. This is a meal that will impress your guests. Since some components can be prepared in advance, your time in the kitchen can be spent creating the perfect stack on the sandwich!
Cast Iron Sear – Pan-seared Flank steak cast iron is just as yummy as the grilled version. It’s true. Pan searing indoors makes this a steak you can make year-round and not have to deal with outside elements. Also, any excuse to use my cast iron pan is always a good day.
Check the recipe card for a complete list of ingredients and amounts to use.
Flank Steak Sandwiches Marinade Ingredients
The flavorful umami marinade ignites your taste buds with such a blast of savoriness! This really is the key to a delicious juicy steak sandwich.
Ingredients for Chimichurri Aioli
Substitutions for the flank steak sandwich can vary depending on what you have on hand or a specific flavor profile.
Substitute 1 teaspoon soy and 1 teaspoon Worcestershire for the 1 tablespoon of Maggi Seasoning. For the steak marinade, you can substitute the Maggi seasoning, which is a rich umami flavor enhancer.
Substitute 1/2 teaspoon of granulated garlic for two minced garlic cloves. If you don’t have garlic on hand or if you do not want to remove it from steak before searing in cast iron, this is a great alternative.
Substitute ½ cilantro with additional ½ cup parsley. The chimichurri aioli uses the same amount of cilantro and parsley. If you are one of the up to 14% of people that have an aversion to cilantro, use all parsley. The bright flavor will still be bright with the fresh jalapeno that is included.
How to Make a Flank Steak Sandwich
Cast Iron Flank Steak
The marinade for the flank steak is prepared the same way if you grill or cook in a cast iron pan. The best part of using your cast iron is you can do this any time of the year if grilling is not an option.
Steak should be pulled out of the refrigerator and marinaded for at least 30 minutes.
Use a larger shallow baking dish or cooking sheet so the steak will lay flat and cover with the marinade on both sides of the steak.
When ready to prepare the steak on the stovetop, use your kitchen’s ventilation fan or other ventilation options. When you get the cast iron over medium-high heat, drizzle 1 teaspoon of high-heat cooking oil like grapeseed oil. You do not need much since the marinade has oil already combined.
When the pan is ready, slightly scrape your meat to remove fresh garlic, and add your meat to start to sear, at this time, you can discard the marinade.
Removing the fresh garlic pieces is done so you don’t burn the garlic. Burnt garlic can be very bitter and we don’t want that to change the taste of our dish.
Cook for 5 minutes, check for a good char on the steak, and flip over to cook for another 3 – 5 minutes. Use your meat thermometer to test, which should read from 120 – 125 degrees. It will raise in temperature while resting. The meat thermometer should read 130 degrees for medium rare.
Remove steak from cast iron and set aside to rest for 5 minutes.
Make to make the Chimichurri Aioli
Visit Chimichurri Aioli, for the complete write-up of information for the recipe.
Combine the first 8 ingredients in the mini food processor and pulse until completely, minced smoothly.
Add kosher salt and mayo, pulse three more times to blend.
To emulsify the olive oil, slowly, a few drips at a time, add the olive oil through the feed tube on the food processor while pulsing consistently to combine the ingredients to a smooth creamy texture.
Store in the refrigerator until ready to use to build the sandwich.
Assemble the Chimichurri Flank Steak Sandwich
Butter the bun or bread roll of choice and brown or toast in a pan over medium heat. Toast until the bread is slightly browned.
Start to build the sandwich, add the lettuce leave to the bottom of the bun, top with 3 -5 pieces of thinly sliced flank steak, spread the top inner bun with a generous amount of chimichurri aioli and top with pickled red onion.
Fold the slices or bread together to combine the sandwich and serve.
Best way to Cut a Flank Steak
Cutting a flank steak for the most tender pieces requires cutting the meat against the grain. You can see the grain running lengthwise with a flank steak with the cut visibly.
Cutting the steak across the grain cuts through the tough fibers and shortens them for a more tender piece.
Tips and Notes
The prepared meal will last in an airtight container in the refrigerator for up to 3 days. This is best for both the steak and the aioli. If you make the pickled red onion, this is a staple item that lasts up to 3 weeks in an airtight container in the refrigerator.
To reheat, you prepare the bun and toppings the same, and you can heat the steak in a skillet or use the steak directly out of the fridge. A cold steak sandwich is delicious. It works either way, once you smush between the warm toasted buttered bun, you are ready to enjoy.
Side Dishes for Steak Sandwich
Flank Steak Sandwich with Chimichurri Aioli Recipe
- Seasoned Cast Iron
Flank Steak Sandwich Ingredients
- 1 – 1-1/2 pound Flank Steak
- 8 leaves red lettuce
- 1/2 cup pickled red onion slices
- 4 rolls Italian or French roll 6 inch
Flank Steak Marinade Ingredients
- 1 teaspoon kosher salt
- 1 teaspoon ground pepper
- 2 cloves garlic, grated substitute: 1/2 teaspoon granulated garlic
- 1 tablespoon Maggi Seasoning
- 3 tablespoon extra virgin olive oil
- 1 tablespoon lemon juice
- 1/2 cup cilantro
- 1/2 cup flat-leaf parsley
- 1 tablespoon shallot minced
- 2 cloves garlic chopped
- 1-1/2 tablespoon jalapeno chopped
- 1/2 teaspoon oregano dried
- 1 tablespoon lemon juice
- 1 tablespoon red wine vinegar
- 1/2 teaspoon kosher salt
- 3 tablespoon mayo favorite brand
- 1/4 cup extra virgin olive oil high quality
Flank Steak Marinade
- Add all ingredients for the marinade in a small mixing bowl and whisk well for a couple of minutes.
Searing the Flank Steak
- Remove the steak from the refrigerator and place in a larger shallow baking dish or cooking sheet so the steak will lay flat cover with the marinade on both sides of the steak.
- The steak should marinate for at least 30 minutes. Do not refrigerate and allow steak to come to room temperature.
- Heat your cast iron to medium-high heat. Turn on the kitchen fan for a well-ventilated cooking space.Once the pan comes to heat drizzle one teaspoon of high-heat cooking oil like grapeseed oil.
- When the pan is ready, slightly scrape your meat to remove fresh garlic, and add your meat to start to sear, at this time, you can discard the marinade.
- Cook for 5 minutes on one side, check for a good sear on the steak, and flip over to cook for another 3 – 5 minutes. Use your meat thermometer to test, which should read from 125℉. It will raise in temperature while resting.
- Rest your Steak. Remove the steak from the cast iron and set it on a cutting board for 5 minutes so the meat can rest.The meat thermometer should read 130℉ for medium rare.
- Combine the first 8 ingredients in the mini food processor and pulse until completely, minced smoothly.
- Add kosher salt and mayo, pulse three more times to blend.
- To emulsify the olive oil, slowly, a few drips at a time, add the olive oil through the feed tube on the food processor while pulsing consistently to combine the ingredients to a smooth, creamy texture.
- Store in the refrigerator until ready to use to build the sandwich.
Build the Sandwiches
- Cut the meat into thin pieces, about 1/4 inch thick.Cutting the flank steak for the most tender pieces requires cutting the meat against the grain. You can see the grain running lengthwise with a flank steak with the cut visibly.
- Toast the buns. Open face the buns and butter and toast in pan over medium heat until slightly brown.
- On toasted bun, add 2 pieces of lettuce to the bottom of the bun.Add flank steak slices on top of lettuce, spread the chimichurri aioli to the top inner bun and add picked red onion on top.
- Fold the sandwich together and do the same for all the sandwiches, and they will be ready to serve.