Combine the marinade ingredients in a small bowl and stir to combine.

Add the chicken breasts to a large, non-reactive bowl and pour the marinade on top. Turn the breasts to ensure all pieces are equally coated. Leave to marinate at room temperature for up to one hour or cover and place in the refrigerator overnight.

To prepare the fajitas, heat 2 tablespoons of olive oil in a large cast iron skillet over medium heat. Remove chicken breasts from the marinade and discard the remaining liquid. Place the chicken breasts in the skillet and cook for 7-8 minutes before turning. Continue cooking another 6-8 minutes, or until chicken is cooked through. Remove from heat and keep warm.

Tip: An instant-read thermometer should read 72°C/160°F when inserted into the thickest part of the chicken. The heat will continue to rise another 5 degrees while the meat rests.

Increase heat to medium-high and add the remaining olive oil to the skillet. Add the sliced peppers and onion and cook for 6-7 minutes, stirring frequently, until crisp tender and nicely browned.

To serve, cut the chicken breasts into thin slices and divide among cast iron fajita platters if using, (see tip below) or individual serving plates.

Tip: For an authentic restaurant-style sizzling fajita presentation – heat the cast iron fajita skillet in a hot oven while preparing the chicken and vegetables. Transfer the cooked ingredients to the hot fajita skillets and serve immediately.

Serve immediately with peppers, onions, sliced avocado, lime wedges, and fresh cilantro, if desired, on the side.