Pat the chicken breasts dry and drizzle with 1 teaspoon of olive oil. Season both sides evenly with the Cajun seasoning, onion powder, garlic powder, paprika, salt, and pepper.

Heat a large skillet over medium-high heat and add the remaining teaspoon of olive oil. Place the seasoned chicken breasts in the hot skillet and cook for 3-4 minutes per side, until golden brown and the internal temperature reaches 165 degrees F. Remove the cooked chicken from the skillet and set it aside.

Reduce the heat to medium. Add the butter to the same skillet. Once melted, add the sliced onion, bell peppers, and diced celery. Sauté for 4-5 minutes, until the vegetables have softened and are beginning to caramelize.

Sprinkle the flour over the sautéed vegetables and stir continuously to combine. Cook this mixture for 2-3 minutes, stirring constantly to prevent the flour from burning.

Gradually pour in the chicken broth while whisking constantly to prevent lumps from forming. Add the chicken bouillon powder and extra Cajun seasoning to taste. Continue to whisk and simmer until the gravy smooths out and thickens, which should take about 2-4 minutes.

Shred or chop the reserved cooked chicken. Stir the chicken back into the skillet with the gravy. Let everything simmer together until the chicken is heated through and the gravy has reached your desired consistency.

Serve the spicy chicken and gravy spooned over fluffy rice, creamy mashed potatoes, or warm biscuits. Garnish with a sprinkle of extra Cajun seasoning or fresh parsley if desired.