Step 1: Prepare the Fajita Seasoning. In a small bowl, combine chili powder, cumin, smoked paprika, garlic powder, onion powder, oregano, salt, black pepper, and cayenne pepper (if using). Mix well.
Step 2: Marinate the Chicken and Vegetables. In a large bowl, combine the sliced chicken, red, green, and yellow bell peppers, and sliced onion. Drizzle with 1 tablespoon of olive oil and sprinkle generously with the homemade fajita seasoning. Toss everything together until the chicken and vegetables are well coated. Let it marinate at room temperature for at least 20 minutes, or refrigerate for up to 2 hours for deeper flavor.
Step 3: Cook the Fajitas. Heat the remaining 1 tablespoon of olive oil in a large cast-iron skillet or heavy-bottomed pan over medium-high heat until hot and shimmering. If your pan isn’t large enough to cook everything in a single layer, work in batches to avoid overcrowding. Overcrowding will steam the ingredients instead of searing them, preventing that desirable char.
Step 4: Sear the Mixture. Add the marinated chicken and vegetable mixture to the hot skillet. Spread it out in an even layer. Cook for 5-7 minutes, stirring occasionally, until the chicken is cooked through (no longer pink inside) and the vegetables are tender-crisp with some charring. The char adds incredible flavor to this chicken fajita recipe.
Step 5: Warm the Tortillas. While the fajitas are cooking, warm your tortillas. You can do this by wrapping them in a damp paper towel and microwaving for 30-60 seconds, heating them in a dry skillet for 15-20 seconds per side, or wrapping them in foil and baking for 10 minutes at 350°F (175°C).
Step 6: Serve Immediately. Transfer the sizzling chicken and vegetable mixture to a serving platter. Serve hot with warm tortillas and your favorite toppings such as salsa, guacamole, sour cream, shredded cheese, fresh cilantro, and lime wedges. Enjoy your delicious homemade chicken fajita recipe!