📖 Instructions

1. **Preheat Your Oven:** Position an oven rack in the center of your oven and preheat to 400°F (200°C). This temperature is key for getting those beautiful charred edges on your veggies and perfectly cooked chicken. Line a large, sturdy rimmed baking sheet (or two if you're making a larger batch) with parchment paper or foil for super easy cleanup. Trust me, this little step saves a lot of scrubbing!
2. **Prepare the Chicken:** Pat your chicken breasts dry with paper towels. This helps the seasoning stick better and encourages a nice sear. Place them on a cutting board and slice each breast lengthwise into thin strips, about 1/2-inch thick. Aim for uniform strips so everything cooks evenly. Place the chicken strips in a large mixing bowl.
3. **Prep the Veggies:** Wash and core your bell peppers. Slice the bell peppers (all three colors, if you're using them, for that vibrant look!) and the onion into thin, uniform strips, roughly 1/4-inch to 1/2-inch thick. Again, consistency in size ensures even cooking. Add these sliced veggies to the bowl with the chicken.
4. **Make the Fajita Seasoning:** In a small bowl, whisk together the chili powder, cumin, smoked paprika, garlic powder, onion powder, dried oregano, salt, and black pepper. If you like a little kick, add the cayenne pepper now. This spice blend is where all the magic happens!
5. **Season and Toss:** Drizzle the olive oil over the chicken and vegetables in the large mixing bowl. Sprinkle the prepared fajita seasoning evenly over everything. Using your hands (or tongs), toss thoroughly until the chicken and veggies are well-coated with the oil and spices. Make sure every piece gets some love!
6. **Spread on the Sheet Pan:** Arrange the seasoned chicken and vegetables in a single layer on your prepared baking sheet. It's crucial not to overcrowd the pan; if the pan is too full, the ingredients will steam instead of roast, and you'll miss out on those delicious caramelized bits. If necessary, use two baking sheets. Ensure there’s a little space between each piece for optimal roasting.
7. **Roast to Perfection:** Transfer the baking sheet to your preheated oven. Roast for 20-25 minutes, or until the chicken is cooked through (reaches an internal temperature of 165°F / 74°C) and the vegetables are tender-crisp with some lovely charred edges. Halfway through cooking (around the 10-12 minute mark), carefully remove the pan from the oven and give everything a good stir or flip with a spatula. This helps ensure even browning.
8. **Rest and Finish:** Once cooked, remove the sheet pan from the oven. Squeeze the fresh lime juice over the fajitas immediately; the heat will help the lime flavor really permeate. Garnish with freshly chopped cilantro, if using. The fresh herbs add a burst of brightness that really complements the rich flavors.
9. **Serve Hot:** Serve your piping hot sheet pan fajitas directly from the pan (or transfer to a serving platter) with warm tortillas, a dollop of sour cream or Greek yogurt, fresh salsa, guacamole, and any other favorite fajita toppings. Enjoy your incredibly easy and satisfying meal! Don't forget, leftovers are fantastic for lunch the next day, too.