01 - In a small bowl, thoroughly mix all components of the Cajun Spice Blend until well combined. Set aside.
02 - Pat the chicken breasts completely dry with paper towels to ensure a crispy sear. Lightly coat both sides of each breast with olive oil, then generously apply the prepared Cajun spice mixture to all surfaces, pressing gently to adhere.
03 - Preheat a large cast-iron skillet over medium-high heat. Add the butter (or dairy-free alternative) and allow it to melt completely, swirling to coat the pan.
04 - Carefully place the seasoned chicken breasts into the hot skillet. Sear for 3 to 4 minutes per side, until a deep, flavorful blackening is achieved. Reduce the heat to medium-low, cover the skillet, and continue cooking for an additional 8 to 10 minutes, or until the internal temperature reaches 165°F (74°C). Remove the chicken from the skillet and allow it to rest for 5 minutes on a cutting board.
05 - While the chicken cooks, rinse the long-grain white rice under cold running water until the water runs clear. In a medium saucepan, bring the chicken broth (or water) and ½ teaspoon of salt to a rolling boil. Add the rinsed rice, stir once, then reduce the heat to low, cover tightly, and simmer for 15 minutes, or until all liquid has been absorbed. Remove from heat and let stand, covered, for 5 minutes before fluffing gently with a fork.
06 - Slice the blackened chicken breasts against the grain into ½-inch thick pieces. Serve the sliced chicken over a generous bed of the cooked white rice. Garnish with chopped fresh parsley and lemon wedges, if desired, for a bright finish.