Make roux by heating oil in a large dutch oven over high heat until almost smoking. Add flour & stir until dark red-brown, about 8 minutes. Immediately add celery, onions, & bell peppers. Cook 5 minutes, stirring & scraping the bottom of the pan often. Mix in bay leaves, salt, oregano, & cayenne. Add & stir together stock, canned tomatoes, sausage,& filet seasoning . Boil 15 minutes. (To add okra: reduce heat & simmer until okra is tender, about 15 minutes). Add shrimp to gumbo & simmer until just cooked through, about 3 minutes.
Serve in bowl & add 1 mound of freshly cooked long-grain rice on top.
1/2 lb. okra, cut into 1/4-inch thick slices.
Salt & pepper is not added during cooking as the natural salt in the ingredients is more than enough to season it. (Please taste prior to seasoning before eating.).