Begin by butterflying the chicken breasts, slicing them horizontally to create thinner portions. This ensures even cooking and reduces the time needed on the skillet. Each breast should be approximately ½-inch thick once sliced.

Poke small holes throughout the chicken using a steak knife. This allows the marinade to penetrate deeply, resulting in enhanced flavor. Place the chicken in an airtight container with the marinade and refrigerate for a minimum of 20 minutes or up to 2–3 hours for optimal results. Extended marination of up to 12 hours is acceptable if time permits.

Remove the chicken from the refrigerator and the marinade, reserving the liquid. Let the chicken rest at room temperature for 15 minutes to avoid uneven cooking.

Heat 2 tablespoons of butter in a cast iron skillet over medium-high heat until melted. Place the chicken in the skillet, cooking it undisturbed for about 4 minutes on one side to develop a golden sear. Flip and cook for an additional 2–3 minutes on the other side.

Add 2 tablespoons of the reserved marinade to the skillet and continue cooking for approximately 6 minutes, ensuring the chicken reaches an internal temperature of 165°F. Transfer the cooked chicken to a plate and cover with foil to keep warm.

In the same skillet, melt the remaining butter. Add the sliced onions, cooking until they soften and become translucent, about 6 minutes.

Incorporate the bell pepper strips, sautéing them until they are tender yet maintain a slight crunch, approximately 8 minutes.

Slice the chicken into strips and return it to the skillet, combining it with the cooked onions and bell peppers. Toss well to blend the flavors, then remove the skillet from heat.