Prepare Marinade: In a large measuring cup combine the ingredients needed for the fajita marinade. Reserve 2 tbsp of the marinade for the vegetables. Set aside.
Prepare Chicken: Clean up the meat being used, remove any excess fat.
Marinate Chicken: Place the meat in a large dish or a plastic bag and pour the marinade over the top, covering the meat.
Seal and place in the refrigerator for 3-6 hours to marinate.
Remove the chicken from the marinade. Discard the marinade.
Cook Chicken: Preheat a cast iron skillet over medium heat with 1 tbsp of olive oil.
Pat the chicken dry and sprinkle both sides with salt and pepper.
Place the chicken in the skillet (don’t crowd the pan, cook in batches if needed) and cook over medium heat for 4-5 minutes. Then turn over and continue cooking the other side for another 4-5 minutes.
Depending on the thickness of the chicken, cooking time may vary. Always check the internal temperature of the chicken to ensure that it reaches 165℉.
Rest Chicken: Once the chicken is done, remove the chicken to a plate to rest.
Cook Vegetables: In the same skillet add the sliced bell pepper and onion.
Pour the reserved marinade over the top of the vegetables and cook for 5-7 minutes while stirring, until the vegetables are softened. Add salt and pepper as needed.
Serve: Slice the chicken across the grain.
Serve the sliced chicken, cooked peppers and onion with soft flour tortillas.