Start by finely chopping your large onion, green bell pepper, red bell pepper, and celery. Season your boneless chicken thighs generously with Cajun seasoning. Set aside.

In a large skillet, heat 2 tablespoons of avocado oil over medium-high heat. Once shimmering, add the seasoned chicken thighs and sear for 3-5 minutes on each side until golden brown.

Lower the heat to medium and add 4 tablespoons of unsalted butter. Gradually whisk in 1/4 cup of all-purpose flour, stirring constantly for about 10-15 minutes until medium brown.

Add the chopped onion, both bell peppers, and celery to the skillet. Stir and sauté for about 10 minutes. Mix in 4 cloves of minced garlic and cook for another minute.

Slowly pour in 3 cups of warmed chicken broth while whisking continuously to avoid lumps. Add browning sauce if using. Return the seared chicken and let everything simmer for 30 minutes.

Remove the chicken, chop into bite-sized pieces, stir back into the sauce, and sprinkle with freshly chopped parsley. Serve over cooked white rice, garnishing with green onions.