Begin by finely chopping the onion, green bell pepper, red bell pepper, and celery, setting them aside as your aromatic base. Mince the garlic and chop the green onions and parsley for later use. Season the boneless chicken thighs generously with Cajun seasoning, ensuring each piece is evenly coated.

In a large skillet, heat avocado oil over medium-high heat. Add the seasoned chicken thighs and sear for about 3–5 minutes on each side until golden-brown. Transfer the chicken to a plate and set aside.

Reduce the heat to medium and add unsalted butter to the skillet. Whisk in all-purpose flour to create a roux and cook for about 10–15 minutes until it reaches a medium-brown color.

Once the roux is ready, add the chopped onion, bell peppers, and celery. Sauté for about 10 minutes and then add minced garlic, cooking for an additional minute.

Whisk in warmed chicken broth, add browning sauce and return the seared chicken to the skillet. Simmer for about 30 minutes, stirring occasionally until the sauce thickens.

Remove the chicken, chop into bite-sized pieces, and return to the pot. Fold in chopped parsley, serve over cooked white rice and garnish with sliced green onions.