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Sirloin Fajitas
These classic beef fajitas feature tender strips of marinated sirloin steak infused with bold, Southwestern-inspired flavors. The simple marinade, made with red wine vinegar, chili powder, oregano, and a touch of sugar, enhances the meat's richness while keeping it juicy and flavorful. Traditionally grilled or pan-seared, the steak is often served with sautéed bell peppers and onions on warm tortillas. This versatile dish is a staple of Tex-Mex cuisine, beloved for its balance of tangy, spicy, and savory notes. Perfect for casual weeknight dinners or festive gatherings.
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Prep Time 15 minutes
Cook Time 10 minutes
Marinating time 8 hours
Total Time 8 hours 25 minutes
Course Main Course
Cuisine Mexican
Servings 4
Calories 362 kcal

Ingredients
  

  • 1½ lbs boneless beef sirloin steak
  • ¼ cup vegetable oil
  • ¼ cup red wine vinegar
  • 1 tsp sugar
  • 1 tsp dried oregano leaves
  • 1 tsp chili powder
  • ½ tsp salt
  • ¼ tsp black pepper

Instructions
 

Step 1: Prepare the Marinade

  • In a medium bowl, whisk together vegetable oil, red wine vinegar, sugar, oregano, chili powder, salt, and pepper.

Step 2: Marinate the Beef

  • Slice the sirloin steak into thin strips.
  • Place the beef in a shallow dish or zip-top bag.
  • Pour the marinade over the beef, ensuring all pieces are well coated.
  • Cover and refrigerate overnight.

Step 3: Cook the Beef

  • Heat a large skillet or grill pan over medium-high heat.
  • Remove beef from marinade and cook in batches for about 4–5 minutes, or until browned and cooked through.

Step 4: Serve

  • Serve hot in warm tortillas with sautéed peppers and onions, if desired.

Tips

  • Slice the beef against the grain for maximum tenderness.
  • Add lime juice to brighten the marinade.
  • Swap beef for chicken or portobello mushrooms.
  • Add sliced onions and bell peppers to the pan for classic fajitas.
  • Cook on a cast-iron skillet for best searing.
  • Increase chili powder for a spicier profile.
  • Add garlic for deeper flavor.
  • Serve with tortillas, salsa, guacamole, or sour cream.
  • If short on time, reduce marinating to 2 to 4 hours.

Nutrition

Calories: 362kcalCarbohydrates: 2gProtein: 38gFat: 22gSaturated Fat: 5gPolyunsaturated Fat: 8gMonounsaturated Fat: 6gTrans Fat: 0.1gCholesterol: 105mgSodium: 150mgPotassium: 614mgFiber: 0.4gSugar: 1gVitamin A: 158IUVitamin C: 0.1mgCalcium: 60mgIron: 3mg
Keyword beef marinade, fajitas, grilling, homemade marinade, Tex-Mex cooking, vintage recipe, weeknight dinner
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