Step 1: Marinate the Steak

1. In a small bowl, combine olive oil, lime juice, garlic, chili powder, cumin, smoked paprika, onion powder, cayenne pepper (if using), salt, and black pepper. Mix well to form a marinade.
2. Place the steak in a shallow dish or resealable plastic bag. Pour the marinade over the steak, ensuring it is evenly coated. Seal the bag or cover the dish and refrigerate for at least 20 minutes, or up to 2 hours for maximum flavor.

Step 2: Prepare the Toppings

1. While the steak is marinating, prepare the taco toppings. Wash and shred the lettuce, dice the tomatoes, chop the onions and cilantro, and slice the avocado. Set aside in small bowls for easy assembly.

Step 3: Cook the Steak

1. Heat a grill pan, cast-iron skillet, or outdoor grill over medium-high heat. Lightly oil the surface to prevent sticking.
2. Remove the steak from the marinade and shake off any excess liquid. Cook the steak for 3-5 minutes per side, depending on the thickness, until it reaches your desired doneness. Use a meat thermometer to check:
   • Rare: 125°F (51°C)
   • Medium-Rare: 135°F (57°C)
   • Medium: 145°F (63°C)
3. Transfer the steak to a cutting board and let it rest for 5 minutes to retain its juices.

Step 4: Slice the Steak

1. Using a sharp knife, slice the steak against the grain into thin strips. This ensures tender pieces that are easy to bite into.

Step 5: Warm the Tortillas

1. Heat the tortillas in a dry skillet over medium heat for 20-30 seconds per side, or until warm and pliable. Alternatively, wrap them in foil and warm them in the oven.

Step 6: Assemble the Tacos

1. Place a few slices of steak in the center of each tortilla. Add shredded lettuce, diced tomatoes, chopped onions, cilantro, and avocado slices (if using).
2. Drizzle with salsa and a dollop of halal sour cream or yogurt, if desired. Serve immediately with lime wedges for extra zest.