In a 2-gallon stockpot, heat oil over medium-high heat. Once oil is hot, add flour and, using a wire whisk, stir constantly until dark brown roux is achieved. Immediately add diced onion, celery, and bell pepper, reduce heat to medium-low, and cook, stirring often, until vegetables are soft, about 20 minutes (roux will darken). 

Add minced garlic and andouille and sauté for 2 minutes Add cold stocks to roux and whisk thoroughly. Increase heat to medium-high, bring to a simmer, adjust heatm and simmer for 20 minutes. Meanwhile, in a separate pan, smother diced tomatoes and fresh okra; finish with green onions and chopped parsley. Add to main pot and simmer for 45 minutes to 1 hour. To finish, quickly sauté shrimp in a separate skillet; when just done, add to gumbo and remove from heat. 

Adjust seasoning with Creole seasoning, pepper sauce, and Worcestershire sauce. 

Adjust flavor and consistency with gumbo filé.