Heat 2 tsp. oil in a skillet over medium heat and brown the chicken on all sides. Cook for about 5 minutes, or until chicken is cooked through. Remove and set aside.
Lower the heat to medium low and add the animal fat and flour. Mix until a paste forms. Continue mixing until the roux turns a light brown, about 5-10 minutes.
Add the green pepper and onion and cook for 3-4 minutes, until vegetables start to soften. Add the chicken and tomatoes and stir to combine.
SLOWLY add the warm chicken stock and wine, just a small amount at a time, until a sauce starts to form. Continue adding the liquid while stirring. The sauce should be thick, but easily stir-able.
Add the Worcestershire sauce and Cajun seasoning and cook on medium low, simmering, for about 5 minutes. Remove from heat and serve over white rice. Garnish with green onions and hot sauce (optional).
Notes
The roux should be a light brown or caramel color when ready. Be sure to stir the roux continuously while making it to ensure it doesn't burn. It will take about 5-10 minutes before it reaches the desired color.
Never add cold liquid to a hot roux. It can cause it to separate and you'll have to start over. Add warm liquid VERY SLOWLY while stirring to make a thick, creamy sauce.
You can add more spice for a spicier etouffee if desired. Start with ¼ teaspoon of cayenne pepper and work your way up depending on how spicy you want it.
If your etouffee is too thin, you will want to thicken it with a cornstarch slurry. Add 1 tablespoon of cornstarch with 1 tablespoon of water in a small bowl and mix to combine.
Add the slurry to the etouffee while simmering, just a small amount at a time, until the desired thickness is reached. Be sure to stir it continuously while adding it.