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Traeger Beef Fajitas

A Traeger pellet smoker may not be the first thing that comes to mind when you think about sizzling beef fajitas hot off the grill, but you can make amazing fajitas on a Traeger. And it’s super easy. This recipe only calls for 5 ingredients with the option to throw peppers straight on the Traeger along with your fajitas. Let’s dive in.

Making a Beef Fajitas Marinade

Next time you’re in Texas, you’ll have to try the beef fajitas from Lupe Tortilla. They’re something special and widely considered some of the best Tex-Mex beef fajitas around these parts. You can even have them made with filet mignon!

We recently asked one of their chefs for the recipe and were surprised to learn it’s a simple combination of 4 ingredients:

  • fajita seasoning
  • sugar “For browning on the grill.”
  • lime juice – “A lot of lime juice.”
  • oil – “To prevent sticking on the grill.”

While he wouldn’t divulge what goes into the fajita seasoning, we figured we could get close enough.

H-E-B Texas Originals Beef Fajitas Seasoning with skirt steak, sugar, and limes

Everyone’s favorite Texas grocer, H-E-B, makes a great beef fajitas seasoning with added tenderizer ingredients. You can use any fajitas seasoning, but I would recommend looking for something with tenderizers like proteolytic enzymes (proteases). And if you’re looking for something else to use your seasoning for, be sure to check out my smoked pulled beef tacos next!

Because as we learned during recipe testing, most restaurants use outside skirt steak while most grocery stores carry inside skirt steak. The former is more tender, and we had trouble matching the tenderness of Lupe Tortilla’s beef fajitas regardless of time in a marinade or cooking to different levels of doneness.

For Ultra Tender Skirt Steak Fajitas

Our Lupe Tortilla chef connection told us they only marinate their skirt steak for 20-30 minutes. We felt this was surprisingly enough time for the beef fajitas to pick up plenty of flavor, but it lacked tenderness. Marinating for longer (3-10 hours) helped, but what helped the most was using manually tenderized skirt steak (pictured below).

tenderized skirt steak with beef fajitas seasoning

You might be able to buy tenderized inside skirt steak in your grocery store but if not, just take a meat tenderizer or mallet to it.

Other common ingredients you’ll see in beef fajitas marinades might include beer, soy sauce, and fruit juices. We tested several batches with different combinations and ultimately decided the straight lime juice marinades were the best.

skirt steak in a lime juice marinade

You’ll want to marinate your skirt steak in a plastic bag or covered bowl with the excess air removed. (If marinating in a bowl, place plastic wrap directly on the steak and up the sides of the bowl.)

With the acidic marinade, you don’t want to go too far beyond the recommended 10-hour marinate time. Otherwise the acid will start doing some weird science things to your skirt steak.

Grilling Beef Fajitas on a Traeger Grill

The secret to great fajitas is a screaming hot grill, which is where the limitations of a Traeger grill or pellet smoker pop up.

You’ll want to set your Traeger to 500ºF or its highest setting and let it preheat for at least 15-20 minutes once it reaches 500ºF. This will ensure the grill grates are as hot as possible and primed for searing.

marinated skirt steak on a Traeger grill

It also helps to grill your beef fajitas near the front edge of the Traeger, where the heat naturally diverts around the drip pan. But speaking of the drip pan, you don’t want to go too far beyond the drip pan. Otherwise your skirt steak drippings will go down the side of your Traeger toward the fire pot.

To grill with the lid open or closed on a Traeger?

You might think leaving the lid open once the beef fajitas are on the grill will trick the Traeger into producing more direct heat, but that’s not the case. The Traeger loses too much heat with the door open and will make searing nearly impossible.

You’ll want to close the lid once the steak goes on the grill and cook for about 5 minutes on the first side before flipping and cooking an additional 30-60 seconds or until the steak is cooked to medium or 135ºF.

How to Slice Skirt Steak and Serve Your Beef Fajitas

While some cuts of beef are tricky to tell which direction the “grain” is running (like our Traeger smoked tri tip), skirt steak is one of the most obvious. You can clearly see the muscle fibers running crosswise in a single direction. You want to slice “against the grain” or in the opposite direction of these muscle fibers.

sliced beef fajitas on a cutting board with tortillas and grilled jalapeño peppers

We like to slice with the grain in the center of the skirt steak to make 4″ to 5″ slices against the grain on both sides.

As for serving, we like to throw tortillas on the grill while it’s still hot to warm while the steak rests. We’ll also slice any grilled peppers into strips and prepare fixin’s like sour cream, guacamole, pico de gallo. And it’s never a bad idea to have rice and beans around.

We always recommend the Traeger charro beans that we served alongside our Mexican smoked pork tenderloin. You could start them ahead of time while the skirt steak is marinating. Our Traeger Mexican street corn salad would also be a great side to throw on at high temperatures alongside your fajitas.

two beef fajitas tacos with Traeger grilled peppers

And if you have leftover beef fajitas, check out my Traeger grilled chicken breast recipe for ideas like taquitos, baked quesadillas, queso smothered burritos, and more.

Okay, that’s everything we have to say about making beef fajitas on a Traeger. If you have any questions about the recipe or ingredients, leave it in the comments below. And once you try these fajitas, be sure to let us know what you think in a recipe review!

Traeger Beef Fajitas

Traeger Beef Fajitas

Yield: 8 Servings
Prep Time: 30 minutes
Cook Time: 10 minutes
Marinate: 3 hours
Total Time: 3 hours 40 minutes

Marinated skirt steak grilled to perfection alongside fajita peppers on a Traeger grill.

Ingredients

  • 2 pounds Skirt Steak*
  • 2 Tablespoons Beef Fajita Seasoning**
  • 1 Tablespoon Sugar
  • 1/2 cup Lime Juice, about 6 limes
  • 2 Tablespoons Olive Oil
  • Optional: Jalapeño, Bell, Poblano, or Mini Sweet Peppers

Instructions

  1. Season the skirt steak with the beef fajitas seasoning and sugar while you juice the limes. Mix the lime juice with the olive oil and add to a resealable bag or container with the skirt steak. Make sure the beef is fully submerged and refrigerate for at least 3 hours and up to 8-10 hours. Avoid marinating too far beyond that. (Optional: Slice the steak in half with the grain for more manageable pieces on the grill.)
  2. When ready to grill, set the skirt steak out at room temperature while you preheat the Traeger to 500ºF with the lid closed for 15 minutes. You want the grill to be as hot as possible before adding the beef.
  3. Optional: For grilled fajita peppers, add peppers straight to the grill around the back edge when the steak goes on. Be sure to turn every 2-3 minutes.
  4. Add the skirt steak along the front edge of the Traeger grill grates where it's the hottest with direct heat. (Don't go beyond the drip pan.)
  5. Cook for 4-5 minutes before flipping and cooking another 30-60 seconds until a medium internal temperature of 135ºF.
  6. Tent the finished steaks with foil and rest for 5-10 minutes before slicing against the grain and serving with the optional grilled peppers, warmed tortillas, and your favorite beef fajitas fixin's.

Notes

*Use tenderized inside skirt steak for best results. Regular inside skirt steak works but can be a little chewy, regardless of how long it's in a marinade or how it's cooked. Restaurants use outside skirt steak that's more tender, but it's difficult to find and the outer membrane needs to be removed during prep.

**I used H-E-B Texas Originals Beef Fajita Seasoning, which is a blend of salt, pepper, garlic, onion, paprika, cayenne, citric acid, and a tenderizer enzyme from papaya. I recommend using a seasoning blend that includes some type of proteases. Soy sauce is a common add-on to include glutamates and proteases for added flavor and tenderness. Source: J. Kenji Lopez-Alt

Nutrition Information:
Yield: 8 Serving Size: about 3 oz
Amount Per Serving: Calories: 245Total Fat: 15gCarbohydrates: 4gProtein: 20g

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