Flavorful Flank Steak Fajitas

fajita marinated flank steak

In February, my sister and I went to Santa Fe and took some classes at the Santa Fe School of Cooking – it was an incredible culinary experience – I highly, highly recommend it for a fabulous getaway for any foodie interested in southwest foods.  I learned so much in just a few days – but I heard one thing that shocked and puzzled me. I attended a class called “Fajitas!,” with Chef Susan Anzalone. She said this –

“Never add acid to marinades for meats. NEVER. It will toughen the meat, just like it does in ceviche. Use zest if you want citrus flavor.”

This stunned me, because for years I have used lime juice in fajita marinades – with chicken and flank steak. So, I did some research seeing what some of my favorite chefs recommend for fajita marinades.

Alton Brown, a culinary hero of mine, calls flank steak “the most marinatable hunk of beef there is” in his book I’m Just Here for the Food. But, he does NOT use citrus in his marinade. On Good Eats, he does use lime juice, but says it does NOT tenderize the meat but only adds flavor. (((Hhmmmm . . . OK, Alton, one question:  if you’re not using juice for tenderizing meat but only flavor, why not use ZEST – it’s 1,000 times more flavorful than juice?)))

Some of my favorite magazines – Bon Appetit, Gourmet and Cooking Light – all use lime juice in their marinades, all recommend varying times for marinating.

And the amazing source America’s Test Kitchen (Cook’s Illustrated February 2007) uses lime juice, but sprinkles it on right before cooking. So, obviously ATK does not recommend citrus as a marinade.

I went to some of my favorite food blogs – Simply Recipes uses lime juice as a marinade. Kalyn’s Kitchen uses just a little lime juice during crock-pot cooking. Serious Eats uses lime and orange juices but a very short marinade time.

Now that grilling season is here, I plan on doing more than my share of feasting on fajitas – but I was confused: how to marinate?

I decided that the only solution in the quest for a perfect fajita marinade was  a true “Donna’s Test Kitchen” test: juice vs. marinade. The two marinades I used were identical except one used zest and one used juice.


I marinated two hunks of flank steak  for one hour on the countertop.

I then sprinkled a little lime juice on both hunks of meat and then cooked the two hunks side by side on the grill with the veggies – same temperature, same length of time.

I took off the meat, let it rest about 10 minutes and sliced it.

The clear, not-even-close winner was the ZEST marinated meat. Both hunks were equally tender – because of thin slicing. But, the ZEST marinated meat was by far the most flavorful.


2 chipotle peppers in adobo sauce
Zest from one lime (about 2 teaspoons full)
1/4 red onion, chopped
3 cloves garlic, diced
1 teaspoon cumin
1 teaspoon kosher salt
1/4 cup extra virgin olive oil

Place all ingredients in a blender and blend until smooth. Place in a zip lock bag with one flank steak (about 1 1/2 pounds). Let stand on counter 1 hour, turning occasionally. ( You can marinate in the fridge overnight – I tried both ways with the same results.)

Remove meat from bag, wiping excess marinade off. Spray both sides of meat with oil.

Grill meat over very high heat for 3 to 5 minutes on each side according to desired doneness. Remove meat from grill and let stand 10 to 15 minutes. Slice very thinly across the grain. Serve with grilled veggies and tortillas.


— posted by Donna


  1. Lynda Christensen says

    Could you elaborate more on the vegetables. Do you marinate them also in the same sauce but different bag. How hot and long do you grill them? Anything else?

  2. Louis says

    I followed your recipe to the letter. Let the meat sit out for 1hr., then turn it over in a glass dish before refrigerating. Let it sit overnite and then grilled it out with a small chunk of oak. These are the very best fajitas I have ever had. I have been cooking fajitas for many, many years down here in Texas. The lime zest is the best.

  3. Todd says

    Donna, I just finished preparing your marinade with a personal twist. I have always enjoyed cooking and have been interested in taking a class like you have described. I’m unable to get away to take the class now, so until then I will rely on people like you for questions. My question to you is…why make a marinade with zest, spices, oil, etc. and wipe away the excess prior to cooking? Is this something you learned about or just a recommendation? It seems like something you would want to cook into the meat? Am I wrong here? Thanks! I’m anxious to try the fajitas tomorrow! Getting ready for the first Texas A&M game tomorrow! Whoop!

    • says

      Great thought, Todd. I guess the reason I suggest removing the marinade is to help get a char on the meat – if it’s too wet from the marinade, it is more likely to steam than brown. If you do cook this as you suggest, please come back and let me know how it turned out. I am always happy to learn!

  4. covert critic says

    Since Karen revived the comments, I’d like to add my 2 cents. Steak was well seasoned, not overwhelming like other marinades I’ve tried. This allowed the meat and veggies to compliment each other. Made for a well-balanced and flavorful fajita.

  5. Karen says

    We used skirt steak and chicken with this marinade and were really pleased with the results! Our dinner guests needed to postpone to one day later, so the meat marinated for an extra day! Didn’t seem to hurt either meat, in fact, it might have made it better! I have never had such delectable, melt-in-your-mouth steak! Our guests took the recipe home with them, and we will definitely be using this recipe again!

    Do you think it would work well with pork to make carnitas?

    • says

      Wow, Karen – THANKS for your reply. You just made my day. And, on the pork – I think it will be FABulous. Give it a try!


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