Grilled Flank Steak Fajitas in a bowl with homemade tortillas

Grilled Flank Steak Fajitas

Smoky, charred flank steak with vibrant capsicum and onions, available in traditional or leaner marinade versions.
Kcal:
275
Protein:
24g
Fat:
17g
Carbohydrates:
8g
Serving size:
100g
Prep:
30 Mins
Cook:
15 Mins
Total:
45 Mins

Ingredients

680g (1.5 lbs) flank steak


60ml (4 tablespoons) olive oil


45ml (3 tablespoons) lime juice


30ml (2 tablespoons) Worcestershire sauce


15g (1 tablespoon) brown sugar


15g (1 tablespoon) ground cumin


10g (2 teaspoons) paprika


10g (2 teaspoons) garlic powder


5g (1 teaspoon) salt


2 capsicums (300g), sliced


1 large onion (200g), sliced

Cooking Instructions

Step 1:
In a mixing bowl, combine 60ml (4 tablespoons) olive oil, 45ml (3 tablespoons) lime juice, 30ml (2 tablespoons) Worcestershire sauce, 15g (1 tablespoon) brown sugar, 15g (1 tablespoon) ground cumin, 10g (2 teaspoons) paprika, 10g (2 teaspoons) garlic powder, and 5g (1 teaspoon) salt.

Step 2:
Place the 680g (1.5 lbs) flank steak in a large resealable bag and pour in the marinade mixture. Seal the bag, removing as much air as possible, and massage to coat the steak evenly.

Step 3:
Refrigerate the marinated steak for at least 2 hours, preferably 4-6 hours for maximum flavour.

Step 4:
Slice 300g (2) capsicums and 200g (1 large) onion, and set aside.

Step 5:
Preheat your grill to high heat (400-450°F / 204-232°C).

Step 6:
Remove the steak from the marinade, pat dry with paper towels, and grill for 4-5 minutes per side for medium-rare (internal temperature of 57°C / 135°F).

Step 7:
While the steak rests, cook the sliced capsicum and onion in a grill basket or skillet for 5-7 minutes until charred and tender.

Step 8:
Slice the steak thinly against the grain, serve with the grilled capsicum and onions, and enjoy with warm tortillas if desired.

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Kcal:
185
Protein:
26g
Fat:
7g
Carbohydrates:
5g
Serving size:
100g
Prep:
30 Mins
Cook:
15 Mins
Total:
45 Mins

Ingredients

680g (1.5 lbs) lean flank steak, trimmed of excess fat


30ml (2 tablespoons) low-sodium beef broth


30ml (2 tablespoons) lime juice


15ml (1 tablespoon) balsamic vinegar


15g (1 tablespoon) monk fruit sweetener


15g (1 tablespoon) ground cumin


10g (2 teaspoons) smoked paprika


10g (2 teaspoons) garlic powder


5g (1 teaspoon) salt


2 capsicums (300g), sliced


1 large onion (200g), sliced

Cooking Instructions

Step 1:
In a mixing bowl, combine 30ml (2 tablespoons) low-sodium beef broth, 30ml (2 tablespoons) lime juice, 15ml (1 tablespoon) balsamic vinegar, 15g (1 tablespoon) monk fruit sweetener, 15g (1 tablespoon) ground cumin, 10g (2 teaspoons) smoked paprika, 10g (2 teaspoons) garlic powder, and 5g (1 teaspoon) salt.

Step 2:
Place the 680g (1.5 lbs) trimmed flank steak in a large resealable bag and pour in the marinade mixture. Seal the bag, removing as much air as possible, and massage to coat the steak evenly.

Step 3:
Refrigerate the marinated steak for at least 2 hours, preferably 4-6 hours for maximum flavour.

Step 4:
Slice 300g (2) capsicums and 200g (1 large) onion, and set aside.

Step 5:
Preheat your grill to high heat (400-450°F / 204-232°C).

Step 6:
Remove the steak from the marinade, pat dry with paper towels, and grill for 4-5 minutes per side for medium-rare (internal temperature of 57°C / 135°F).

Step 7:
While the steak rests, cook the sliced capsicum and onion in a grill basket or skillet for 5-7 minutes until charred and tender.

Step 8:
Slice the steak thinly against the grain, serve with the grilled capsicum and onions, and enjoy with lettuce wraps if desired.

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Grillwisehub FAQ for:

Grilled Flank Steak Fajitas

What's the best technique for grilling flank steak to ensure it stays tender rather than tough?

For perfectly tender flank steak, focus on these three key techniques: First, marinate the meat for the full recommended 4-6 hours, as the acids in the lime juice and Worcestershire sauce help break down tough muscle fibres. Second, always grill at high heat (400-450°F / 204-232°C) to quickly sear the outside while keeping the inside juicy. Finally, the most crucial step is slicing the steak thinly against the grain (perpendicular to the visible muscle fibres), which shortens the tough fibres and dramatically improves tenderness. For medium-rare, aim for an internal temperature of exactly 57°C (135°F) and allow the meat to rest for 5-10 minutes before slicing to redistribute juices.

How can I make these fajitas suitable for a keto or low-carb diet?

The low-calorie version of this recipe is already well-suited for keto or low-carb diets with only 5g of carbs per serving. To make it even more keto-friendly, replace the monk fruit sweetener with 5g (1 teaspoon) of erythritol or simply omit it altogether. Serve the fajitas in lettuce cups rather than tortillas, or alongside cauliflower rice seasoned with lime and coriander. This meal offers an excellent protein-to-fat ratio (26g protein to 7g fat, or 79% protein, 21% fat) making it ideal for those on high-protein, low-carb nutritional plans. The traditional version can also be adapted by omitting the brown sugar and using lettuce wraps, which would reduce carbs to approximately 5-6g per serving.

What are the most common mistakes people make when preparing flank steak fajitas?

The three most common mistakes with flank steak fajitas are: First, skipping the marinating time—this cut absolutely requires the full 4-6 hours to tenderise and develop flavour, not the minimum 2 hours. Second, overcooking the meat—flank steak becomes noticeably tough beyond medium doneness, so use a meat thermometer and remove it from the grill at 57°C (135°F) for medium-rare. Third, slicing with the grain instead of against it—this single mistake can make even perfectly cooked flank steak nearly impossible to chew. Also, avoid overcrowding your grill when cooking the vegetables, as this leads to steaming rather than the desirable charring that gives fajitas their distinctive smoky flavour.

How much calorie and fat reduction does the low-calorie version offer, and what nutritional benefits does it provide for fitness enthusiasts?

The low-calorie version provides a significant 90-calorie reduction per serving (185 vs 275 calories), with fat content reduced by 10g (7g vs 17g)—that's a 59% reduction in fat while maintaining similar protein levels (26g vs 24g). This dramatically improves the protein-to-calorie ratio, making it excellent for muscle building and recovery. The macronutrient breakdown shifts from approximately 35% protein, 55% fat, and 10% carbs in the traditional recipe to a much more fitness-friendly 56% protein, 34% fat, and 10% carbs in the low-cal version. The balsamic vinegar substitution also provides polyphenols with anti-inflammatory properties that may aid post-workout recovery. This leaner version is particularly suited for athletes in a cutting phase who need to maintain high protein intake whilst reducing overall calories.

What's the best way to store and reheat leftover flank steak fajitas without drying out the meat?

To preserve the quality of your leftover fajitas, store the meat and vegetables separately in airtight containers in the refrigerator for up to 3 days. Never bring cold meat to room temperature before reheating (food safety risk). If you have a sous vide setup, reheating vacuum-sealed steak at 52°C (125°F) for 30 minutes delivers the best results with nearly fresh-cooked quality. For a quick option, stir-fry the vegetables in a hot pan for 2-3 minutes to restore their charred flavour while maintaining some crispness, add the steak briefly with a splash of beef broth just until warmed through (30-45 seconds)—this prevents overcooking while adding moisture.