To a small bowl, mix all the fajita seasoning ingredients. (1 tablespoon cornstarch, 1 teaspoon chili powder, 1 teaspoon kosher salt, 1 1/2 teaspoon smoked paprika, ½ teaspoon onion powder, ½ teaspoon garlic powder, ¼ teaspoon cayenne pepper, and 1 teaspoon ground cumin)
Heat 1 tablespoon of the 2 tablespoons olive oil in a large skillet over medium-high heat. Add the 1 large onion and 2-3 garlic cloves together and sauté for 2-3 minutes. Add the 2 medium bell peppers, then sprinkle with ½ of the fajita mix, and cook for 3 more minutes. Set aside.
Cut a lengthwise pocket into each of the 4 large chicken breasts. Rub the chicken all over with the remaining fajita seasoning, then stuff each of the pockets with a spoonful of the fajita-pepper mixture and 1 cup cheddar cheese. (divided equally). Seal with a toothpick by inserting it diagonally to keep the stuffing in.
To the same skillet, add the remaining 1 tablespoon of the olive oil and sear the chicken breast for 4-5 minutes per side.
Next, add ¼ cup of water to the pan, cover, and cook over low heat for 6-8 minutes, or until the chicken is fully cooked through.
Garnish with Fresh parsley and serve with lime wedges if desired.
Notes
Cheese: you may use any other cheese, like provolone, mozzarella, or Monterey Jack
Bell peppers: Use any colored bell pepper of your choice
You will need to cover the pan to allow the chicken to fully cook. Don't try to cook it too quickly over high heat.
Store leftovers in the fridge for up to 5 days.
To reheat, microwave in the oven for 60-90 seconds. To reheat in the oven, preheat the oven to 375 F. Wrap the stuffed chicken breast in foil, then place it in the oven for about 8-10 minutes.