Begin by making a roux in a large stockpot. On low heat, add the oil and then gradually add flour until both flour and oil are well combined. Stir constantly until the roux reaches a medium-dark brown color. This will probably take about 20-25 minutes. (Roux can burn quickly, so pay close attention. If it burns, you will need to start over!)

Meanwhile, saute the sliced andouille until outside of slices turns dark in color, about 15-20 minutes on medium-high heat. (This step adds a nice texture to the sausage once it goes into the gumbo.)

Once the roux is done, add the onions, bell peppers, and celery. Stir well.

Add the chicken stock, water, and tomatoes.

Bring mixture to a light, rolling boil.

Boil for about 45-60 minutes, then add the chicken and tasso.

Once chicken begins to fall off of the bone (about 30 minutes), strain out all of the chicken pieces and debone.

Discard bones.

Place chicken back into the stockpot along with the sliced andouille.

Bring gumbo back to a slow, rolling boil and cook for another 45-60 minutes.

Serve over white rice with several slices of fresh crusty bread. (Once gumbo has been dished into bowls, add approximately 1/2 tbsp gumbo file. Stir well.)