Easy Flank Steak Fajitas (Weeknight-Friendly)

These Easy Flank Steak Fajitas are the dinner you make when flank steak is a good price at the store, or when you want a lean, easy steak recipe that doesn’t require much planning.

Flank steak is one of the leanest cuts of red meat and cooks quickly over high heat, which makes it perfect for fajitas. Combined with sautéed peppers and onions and wrapped in warm tortillas, this is a simple, satisfying meal that feels satisfying without being heavy. I make it at least every other week!

Instead of a traditional marinade, this recipe uses a reverse marinade, which is faster and less likely to burn. The flank steak is seasoned, seared, and then rested in a lime-garlic mixture to soak up all flavors and keep the lime juice bright (not burned). The fact that it’s faster is a huge win for weeknight dinners.

Tip: If this is your first time cooking flank steak or you need a refresher, you may want to check out my Perfect Flank Steak Recipe over here.

Why You’ll Love Flank Steak Fajitas

• Fast and reliable: About 30 minutes of active cooking
• Lean but flavorful: Flank steak stays tender when cooked and sliced correctly
• No advance marinade: The reverse marinade saves time and avoids scorching
• Balanced and filling: Protein, vegetables, and satisfying texture
• Easy to adapt: Naturally dairy-free and simple to make gluten-free

Ingredients You’ll Need

For the steak

• 1½ pounds flank steak (anywhere from 1-2 pounds)
• Kosher salt or fine grain sea salt
• Freshly ground black pepper
• Avocado oil or another high-heat oil, for searing

Reverse marinade

• 3 tablespoons fresh lime juice (from about 2 large limes), plus more for serving
• 2 cloves garlic, grated or pressed
• 2 tablespoons extra-virgin olive oil
• 1 teaspoon ground cumin
• ½ teaspoon sea salt
• Freshly ground black pepper

For the fajitas

• 1 large yellow onion, sliced
• 1 red bell pepper, sliced
• 1 green bell pepper, sliced
• 1 clove garlic, minced, pressed or grated

For serving

• Taco-size flour tortillas (or tortillas of choice)
• Optional: avocado, sliced or mashed
• Optional: chopped fresh cilantro

How to Make Flank Steak Fajitas

1. Season the flank steak & bring to room temp. Generously season both sides with kosher salt.
   • If you have time, let it sit at room temperature for 30–60 minutes. This helps the steak cook more evenly, but if you’re short on time, you can skip this step.
   • Cut the steak into sections before cooking: If your flank steak is long or uneven in thickness, cut it into 3–4 shorter pieces before searing. They cook more evenly and a bit faster, and you’re slicing the steak anyway before serving.
2. Make the marinade and chop the veggies. While the steak comes to room temp, make the reverse marinade by combining the lime juice, grated garlic, olive oil, cumin, sea salt, and a few spins of black pepper in a small bowl. Set aside.
3. Cook the steak. Pat the steak dry with paper towels and heat a large (12-inch if you have it) skillet over medium-high heat until hot, then add a generous glug of avocado oil. Sear the steak for 3–5 minutes per side, until nicely browned on the outside and still pink in the center. If it’s smoking alot and not cooked through, turn the pan to medium and cook until desired doneness (typically 135–140°F)
4. Reverse marinate the hot steak. Transfer the steak immediately to a shallow bowl or dish, pour the marinade over the top, and tent loosely with foil. Let it rest for 10 minutes so the steak absorbs the marinade and finishes cooking gently. Now is a good time to warm the tortillas if needed.
5. Cook the peppers and onions: While the steak rests, return the skillet to medium heat. Add another splash of oil if needed, then add the sliced onions and peppers. Cook until softened, about 7–8 minutes. A few minutes in, add a splash of water to deglaze the pan and pick up the browned bits. About 5 minutes into cooking the vegetables, add the garlic (carefully, to avoid burning), ¼ teaspoon of salt, and black pepper. Stir and cook just until fragrant 1-2 minutes, then turn off the heat. Adjust seasoning to taste.
6. Plate: Warm the tortillas in the oven, microwave, or directly over a gas flame and keep them wrapped in a towel. Transfer the steak to a cutting board and slice the steak against the grain into thin strips or bite-sized pieces. Add it back to the pan with the peppers and onions (off the heat) to keep warm. Be sure to slice against the grain for the best texture.
7. To Serve: Let’s everyone build their own, we like avocado on the bottom, then steak and veggies, then top with cilantro. Serve immediately.

Variations & Substitutions

• Skirt steak: Skirt steak is the more traditional cut of beef for fajitas and works just as well here. It’s slightly fattier than flank steak and very flavorful, but benefits from the same quick sear and slicing against the grain.
• Choose your toppings: We like to keep it simple with avocado and cilantro, but you can add salsa, pico de gallo, guacamole, sour cream, cheese, spicy pepper, or hot sauce. Use your favorite taco toppings.
• Different vegetables: We prefer traditional fajitas with peppers and onions, but feel free to swap in sliced poblano peppers, mushrooms, or even thinly sliced zucchini to use up what you have. Just aim for vegetables that cook quickly and soften without releasing too much water.
• Gluten-free: Use corn tortillas or your favorite gluten-free tortillas to keep the meal completely gluten-free. Or, skip the tortillas and serve it over cooked white rice or cooked brown rice.
• Switch up the reverse marinade: Add a few tablespoons of fresh orange juice, a teaspoon of chipotle in adobo, chili powder, spices or other flavor combos. Once you learn this method, you can play with the flavors and ratios to make it your own.
• Citrus swap: Lime juice gives the best flavor, but lemon works if that’s what you have. If using lemon, add a small splash of water to mellow the acidity.
• Extra heat: Add sliced jalapeño to the pan with the peppers and onions, or finish with a dash of hot sauce.
• Hate cilantro? Leave it out!

Chef Tips for the Best Steak Fajitas Recipe

• Use a hot pan: Whether you’re using cast iron or stainless steel, let the pan heat fully before adding the steak. A hot pan is what gives you a good sear without overcooking the meat.
• Choose the right oil: Use a high–smoke point oil like avocado oil, beef tallow, or grapeseed oil for searing. Save extra-virgin olive oil for the marinade only.
• Don’t skip the rest: Resting the steak in the marinade allows it to finish cooking gently and absorb flavor. This step makes the steak noticeably juicier.
• Slice against the grain: Flank steak has long muscle fibers. Cutting across them is essential for tenderness — it’s one of the most important steps in the recipe.
• Deglaze for flavor: That small splash of water added to the pan while cooking the vegetables lifts the browned bits left from the steak, adding depth to the fajitas without extra ingredients.
• Serve off the heat: Once the steak is sliced, keep it off the heat to prevent overcooking. Adding it back to the warm pan (with the heat off) keeps everything juicy and tender.

Storage & Meal Prep

• Store leftover steak and vegetables in an airtight container in the refrigerator for up to 3 days
• Keep tortillas stored separately so they don’t dry out
• Reheat gently in a skillet over medium heat

Leftovers make an excellent lunch or quick dinner the next day.

Want more healthy home cooking inspiration? Find more taco recipes here.

Flank Steak Fajitas FAQs

Why is flank steak good for fajitas?
Flank steak is lean, flavorful, and cooks quickly over high heat. When sliced against the grain, it stays tender and works perfectly for fajitas.

What is a reverse marinade?
Instead of marinating before cooking, the steak rests in the marinade after searing. This prevents burning and keeps the flavor fresh and bright. Plus, you don’t have to think ahead to marinate the meat.

Do I have to let the steak come to room temperature?
It helps the steak cook more evenly, but if you’re short on time, the recipe still works well without it. In general, letting meat sit out for 30–60 minutes helps it cook more evenly because you’re not starting with a very cold center. Meat coming straight from the fridge (around 40°F) needs more time to heat through, which can lead to the outside browning before the inside is cooked to your liking. That said, if you’re short on time, you can absolutely skip this step—just keep the heat slightly lower if needed and cook until the steak reaches your desired doneness.

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