Gumbo - Shrimp, Tasso Ham, Andouille Sausage, Chicken, File' - cooking recipe

Ingredients

1 1/2 lbs andouille sausages (cut bite sized)
2 1/2 lbs tasso (cut bite sized, Tasso is different from regular ham)
2 lbs chicken thighs (boneless, skinless, cut in quarters)
2 lbs shrimp, large (peeled and deveined)
12 cups chicken stock (homemade if you have it, use an old rotisserie chicken carcass)
2 cups celery (chopped)
4 cups onions (chopped)
2 cups bell peppers (chopped)
2 tablespoons fresh garlic (minced)
1 teaspoon fresh thyme (removed from stem)
3 bay leaves (whole)
2 cups vegetable oil
2 cups all-purpose flour
vegetable oil, as needed for browning meats
file powder
Italian parsley, fresh, chopped

Preparation

Separately, chop / prepare all ingredients necessary as defined above and set aside.
Heat a large heavy pot (cast iron / enameled cast iron) on medium high until pre-heated. Add some oil and saute each meat separately and in batches to brown nicely. (A pain, but worth it, I promise). Start with Andouille, then Tasso, and chicken. Some of the meat will stick and that is perfect. It imparts a rich flavor that is important to your gumbo. After browning, set aside.
ROUX: This is a critical step that requires constant tending. The goal is to cook this flour until it is somewhere between brown and black without burning it.Go for the color of a Hershey's kiss or darker. It is required to make the gumbo you want to make and well worth it. This takes me 45 minutes to an hour to get the right color. Each time I make gumbo I try to get it darker and darker. Don't be afraid to turn the heat up and down even if it take you longer. Better to take longer than to burn it. If you have black flecks, you have burned it and must start over. (You can do it perfectly though!).
Add 2 cups oil and 2 cups flour to the.
Pour the 2 cups oil and 2 cups flour into your pot. Stir slowly, consistently until it is brown / black. (It will happen. Just keep going.).
When the roux has reached the desired color, add the chopped celery, onion and peppers and stir constantly for 8-10 minutes. Be careful not to burn. Cast irons hold heat well, so feel free to lower your temperature and just cook longer).
Add chicken stock one ladle / cup at a time, stirring in between each addition to keep temperature and to make sure your roux doesn't break).
Add all meats and drippings (except shrimp) and reduce to simmering uncovered for three hours stirring delicately and occasionally. Add shrimp and cook for 15 minutes more.
Taste a little to adjust seasonings to your preference and then refrigerate in pot for three - four days.
Reheat when ready to serve. Serve over rice topped with fresh parsley. Allow each diner to sprinkle their own file' for thickening and flavor.