Haris's Flank Steak Fajitas with Sizzling Peppers & Onions
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Flank Steak Fajitas
with Sizzling Peppers & Onions
Halal grass-fed flank steak marinated in citrus, garlic, and smoky spices, grilled over high heat, and sliced thin against the grain. Served sizzling with caramelized peppers and onions in warm flour tortillas.
Flank steak is the fajita cut. Its long, flat muscle structure and bold beef flavor absorb marinades deeply and develop a beautifully charred surface over high heat while staying pink and juicy inside when caught at medium-rare. The two rules that separate a great fajita from a tough one: marinate for at least two hours to break down the surface fibers, and always — without exception — slice against the grain. The grain on a flank runs lengthwise and is clearly visible; cutting across it turns tough into tender.
We use Thomas Farms halal grass-fed flank steak — the grass-fed flavor is noticeably bolder and more complex than conventional, which means even a simple citrus-cumin marinade produces something that tastes like serious cooking. The 12oz pack feeds three to four people generously with plenty of peppers alongside.
Slice against the grain — the single most important step: Flank steak has very long, visible muscle fibers running lengthwise. Cutting parallel to them gives you long, stringy, chewy pieces. Cutting perpendicular — straight across those lines — gives you short, tender, juicy bites. Look at the steak before you cut. Rotate it if needed. Cut across the lines every time.
Ingredients
For the steak & marinade
- 12 ozThomas Farms halal grass-fed flank steak
- 3 tbspFresh lime juice (2 limes)
- 2 tbspFresh orange juice
- 2 tbspOlive oil
- 3 clovesGarlic, minced
- 1 tspGround cumin
- 1 tspSmoked paprika
- ½ tspChili powder
- ½ tspDried oregano
- 1 tspSalt
- ½ tspBlack pepper
- HandfulFresh cilantro, chopped
Marinade time limit — 4 hours max: The citrus acids tenderize beautifully between 2–4 hours. Beyond 6 hours the outer layer of the meat becomes mealy in texture. Set a timer.
Peppers, onions & tortillas
- 3Bell peppers (red, yellow, green), sliced
- 2 largeOnions, sliced into half-moons
- 2 tbspOlive oil
- ½ tspCumin
- ½ tspSalt
- 8Flour tortillas, warmed
For serving
- 1Avocado, sliced
- ½ cupSour cream or plain Greek yogurt
- ½ cupFresh salsa or pico de gallo
- 1Lime, cut into wedges
- HandfulFresh cilantro
Get the peppers properly caramelized: Cook peppers and onions over medium-high heat and resist stirring too often — they need contact time with the hot pan to develop sweet, charred edges. Stirring constantly produces steamed, soft vegetables instead.
Instructions
Phase 1 — Marinate (2–4 hours)
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1
Marinate the flank steak
Combine lime juice, orange juice, olive oil, garlic, cumin, paprika, chili powder, oregano, salt, pepper, and cilantro in a zip-lock bag or shallow dish. Add the flank steak and coat thoroughly. Refrigerate for 2–4 hours. Pull from the fridge 20 minutes before grilling — a cold steak on a hot grill cooks unevenly.
Phase 2 — Cook the peppers & onions
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2
Sauté peppers and onions until caramelized
Heat olive oil in a large cast-iron skillet or heavy pan over medium-high. Add the sliced peppers and onions with cumin and salt. Cook for 12–15 minutes, stirring every 3–4 minutes, until the edges are deeply caramelized and the onions are sweet and soft. Keep warm while you grill the steak.
Phase 3 — Grill the steak
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3
Grill over highest heat
Preheat the grill or a cast-iron skillet to the highest possible heat. Shake the excess marinade off the steak — a wet surface steams instead of searing. Grill 4–5 minutes per side without moving to develop a deep char. The steak is thin and cooks quickly; target 130–135°F for medium-rare.
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4
Rest 5 minutes then slice against the grain
Transfer to a cutting board and rest for 5 minutes. Now identify the muscle fibers — they run lengthwise along the steak. Slice at a 45° angle, perpendicular to those fibers, into thin strips. This is the move that makes flank steak tender. Cutting with the grain produces something chewy and disappointing.
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5
Serve sizzling
Return the pepper and onion pan to high heat for 60 seconds until sizzling again. Lay the sliced steak on top. Bring to the table sizzling. Serve with warm tortillas and all the toppings — avocado, sour cream, pico de gallo, fresh cilantro, and a hard squeeze of lime over everything.
How to build the perfect fajita
Serving suggestions
Variations
🌯 Fajita bowl
Skip the tortillas. Serve everything over cilantro-lime rice with black beans and a drizzle of chipotle yogurt sauce. Lower carb, same flavors.
🌶️ Chipotle marinade
Add 2 tbsp adobo sauce from canned chipotles to the marinade. Smokier, deeper, and more intensely spiced — excellent for those who want more heat.
🍋 Al pastor spice
Add ½ tsp each of dried ancho chili and guajillo chili powder to the marinade for a deeper, more complex spice profile inspired by al pastor.
🧀 Quesadilla
Layer leftover sliced steak and peppers between two tortillas with shredded cheese. Press in a dry pan for 2 minutes per side — the best use of leftovers.
🥗 Fajita salad
Serve steak and peppers over romaine with corn, black beans, cherry tomatoes, and a cumin-lime dressing. Bright and substantial.
🌮 Street taco style
Use small corn tortillas (double-stacked), skip the peppers, and serve with just white onion, cilantro, and salsa verde. Stripped back and excellent.
Storage
Cooked steak
Keeps 3–4 days refrigerated. Reheat briefly in a hot skillet — 60 seconds per side. Don't overcook on reheat or it toughens.
Freeze in marinade
Freeze raw steak in the marinade for up to 1 month. Thaw overnight in the fridge — it marinates further as it thaws.
Peppers & onions
Keep 4 days refrigerated. Reheat in a hot pan for 2 minutes. Excellent in eggs, rice bowls, or sandwiches throughout the week.
Nutrition (per serving, approx.)
* Estimates per serving (2 fajitas) based on 4 servings including tortillas and peppers. Does not include avocado or sour cream.
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