- Tender meat
- Brown exteriors and juicy interiors
- Rich, savory flavor
- Bright mojo sauce
Back when I was a line cook at Craigie Street Bistrot in Cambridge, Massachusetts, we had a nightly routine involving skirt steak. The end pieces were never plated because they were too small to show off the beautifully cooked beef, so the chef habitually tossed them into a “meat bucket.” At the end of the night, the tidbits were heated up under the broiler for a postshift snack. Trust me when I tell you (after many, many bites) that this fatty cut is intensely beefy, tender, and juicy—a true cook's treat.
Skirt steak is long, narrow, and only ½ to 1 inch thick. Because it's so thin, you need to cook it over high heat to ensure that the outside is well browned by the time the interior is tender and juicy. That makes a grill, which is easy to get blisteringly hot, the best tool for the job. As a bonus, a large grill grate can accommodate all the ribbon-like steaks at the same time instead of in batches.
Skirt steak is also a great candidate for a marinade. In the test kitchen, we often shy away from marinating meat because the flavorings don't penetrate much beyond the surface of a thick, smooth cut. But because skirt steak is so thin, with loose, open fibers and lots of nooks and crannies, a marinade can have a big effect.
We don’t typically marinate steak since we have found that marinades don’t penetrate more than a few millimeters beyond its surface. For a thick-cut steak, that means minimal flavor impact. But skirt steak is different: It has much more surface area than other cuts. And because it’s so thin, the ratio of surface area to volume is quite large. That means there is a lot of exterior space for a marinade to flavor. If you look carefully, the grain of a skirt steak forms peaks and valleys like, well, a pleated skirt: The amount of fabric required to make a pleated skirt is much greater than the amount required to make a straight skirt. To illustrate this, we placed a measuring tape on a skirt steak and carefully pressed it into the valleys. When we removed the measuring tape, we found that the surface area for a skirt steak was three times that of a strip steak of the same weight.
I knew exactly what I wanted to bathe my steaks in: a garlicky, citrusy, Cuban-style mojo that would really stand up to the rich, buttery beef. Once I'd perfected the marinade and the steak cookery, I planned on whipping up a complementary sauce to drizzle onto the meat.
Skirt steaks are often rolled up for packaging because when they are unrolled, they can be nearly 2 feet long. I divided 2 pounds of steak (enough to serve four to six people) into 6- to 8-inch lengths.
Then came the marinade: I stirred together ½ cup of orange juice and 2 tablespoons of lime juice (my substitute for the difficult-to-find sour orange juice traditionally used in mojo) and added the usual seasonings: ground cumin, dried oregano, plenty of minced garlic, and a few red pepper flakes. I also made sure to add a good amount of salt—1½ teaspoons for the 2 pounds of meat. The salt would not only season the meat—it would also dissolve some proteins and loosen the bundles of muscle fibers, making the steak more tender, and hold in water to keep the meat moist.
I pulled out a 13 by 9-inch baking dish, which would be a good vessel for soaking the steaks with minimal overlapping. I refrigerated the steaks for an hour, flipping them at the 30-minute mark to make sure both sides got coated with marinade.
When I removed the steaks from the marinade, I thoroughly patted them dry with paper towels since any excess moisture would inhibit browning; I then rubbed them with a light coating of oil. Over a hot fire (created by distributing 6 quarts of lit coals evenly over half the grill) the steaks cooked to medium (130 degrees) in 6 to 8 minutes. Although we bring most steaks to medium-rare (125 degrees), we have found that the tougher muscle fibers of skirt steak need to hit 130 degrees before they shrink and loosen enough to turn perfectly tender.
I gathered my colleagues grillside to have a taste, and the feedback rolled in: The mojo flavor was coming through beautifully, but the steaks could taste even beefier. Also, the browning was good but not great.
I had ideas about how to address both problems, so I reached for the two skirt steaks that had arrived in that morning's delivery. I was surprised to see that one was almost twice as wide as the other. But they looked similar otherwise, so I carried on.
This time I added a little soy sauce to the mojo marinade (to compensate, I halved the amount of salt). Soy sauce can be a secret weapon in marinades: Its salt seasons, and its glutamates enhance savory flavor.
Once the steaks were out of the marinade and patted dry, I incorporated an ingredient for better browning: baking soda. Added to the oil I had been rubbing onto the steaks, baking soda would help create more substantial browning by raising the meat's pH. The higher its pH, the better meat is able to hold on to water, so it browns instead of releasing the moisture onto the grill grates and creating steam. A higher pH also speeds up the Maillard reaction, making the treated meat brown even better and more quickly.
I was pleased to see the steaks rapidly develop a deep sear on the grill. This was a signal that they were likely done cooking, so I slid them to the cooler side of the grill to take their temperature (their thinness made temping them on the hotter side risky because they could easily overcook). Sure enough, they registered 130 degrees, so I gave them a 10-minute rest to allow the juices to redistribute throughout the meat. As I sampled a few slices, I was happy to find that the meat was not just deeply seasoned but also had an even beefier flavor than before, thanks to the umami-rich soy sauce.
However, the steaks' texture was a different story: Even though I'd soaked both the narrow and the wide steaks in the same marinade and cooked them on the same grill to precisely 130 degrees, the narrow steak was much more tender than the wide one. It was only after speaking to several butchers that I understood why: It turns out that there are two types of skirt steak—the inside skirt and the outside skirt—that come from separate parts of the cow and therefore have markedly different textures.
There are two types of skirt steak: inside and outside. The inside skirt comes from the transverse abdominal muscle and is rather tough; the more desirable outside skirt comes from the diaphragm and is quite tender.
If you have trouble finding skirt steak, that’s because it’s a hot commodity: There are only four skirt steaks (two outside, two inside) on each cow.
I prepared one more batch, making sure to use outside skirt steaks. While the meat marinated, I started gathering citrus, garlic, and spices for the mojo sauce I'd been planning. But wait: All the ingredients I needed were already in the leftover marinade. Why not reuse it? I poured it from the baking pan into a saucepan, brought it to a boil to make it food-safe, and took a taste. It needed richness and a little extra acidity to become a sauce, so I stirred in a little lime juice and extra-virgin olive oil. I also tossed in orange and lime zests to give the sauce more of the bright, tropical flavor typical of sour oranges.
Once the steaks were off the grill and had rested, I carefully sliced them against the grain and at an angle before drizzling on the mojo sauce. My favorite steak had now realized its full potential: The beautifully seared meat was rich, well seasoned, juicy, and tender, and the vibrant sauce played off of it beautifully.
Choosing the outside skirt steak instead of the tougher inside skirt steak helps ensure tender meat.
Brown exteriors and juicy interiors
We rub the steaks with baking soda, which encourages browning, and then grill them over high heat to ensure that they cook to medium and brown nicely in the same amount of time.
Rich, savory flavor
The soy sauce in our mojo marinade brings salt and glutamates to our steaks; the former seasons the meat, and the latter boosts its beefiness.
Bright mojo sauce
We turn the marinade into a vibrant, flavorful sauce by boiling it to make it food-safe and then adding lime and orange zests, lime juice, and extra-virgin olive oil.