Heat butter and oil in a large stock pot over medium high heat until butter is melted.
Gradually add flour, stirring constantly to make a roux. Continue stirring for 8 minutes until roux becomes dark brown, similar to the color of chocolate.
Reduce heat to low.
Add onions, green bell peppers, celery, Italian seasoning, parsley, sausage, chicken and broth.
Bring mixture to a boil. Reduce heat to low, cover and simmer for 30 minutes, stirring often.
Add the okra, Creole seasoning, sugar, picante sauce and bay leaves.
Return to a simmer, cover, and cook for 1 hour, stirring every 15 minutes.
Remove and discard bay leaf.
Place a generous amount of cooked rice into individual bowls.
Pour gumbo over rice.
Sprinkle with file powder if desired.