Season the chicken with salt and pepper to taste (The chicken can be marinated in olive oil and black pepper overnight. Add salt last minute if marinated) Make a dark roux- In a heavy iron skillet (prefer cast-iron), heat the vegetable oil over medium heat.
Add the flour.
With a wooden spoon, stir constantly and thouroughly, until the flour mixture reached an even chocolate color, about 15 minutes (black flecks means it's burned and will be bitter. Start over).
Carefully add the onions, celery and Bell pepper.
Stir constantly for 60 seconds.
Add Garlic, stir to mix, and add the chicken.
Stir to coat the chicken with the roux mixture.
CAREFULLY and slowly, add the chicken stock.
Chicken mixture can be transferred to a larger pot at this point. A Dutch oven is recommended.
Cover the chicken with water, bring to a boil.
Place the lid on the pot, reduce heat and simmer for 45-50 minutes.
Stir occasionally, Sauce should be thickened.
Just before serving, add chopped parsley to taste, season with salt and red pepper to taste.
Serve over hot white rice.
Hint: For saving leftovers, store the rice and the sauce in seperate containers.