Chicken and andouille sausage gumbo

This makes one batch. I quadrupled this recipe for the wedding. Tomorrow's recipe: seafood gumbo.

1 cup vegetable oil
1 cup flour
1 ½ cups chopped onions
1 cup chopped celery
1 cup chopped bell peppers
1 lb andouille sausage (kielbasa also works), sliced
1 ½ teaspoon salt
½ teaspoon cayenne (but I ended up using much, much more)
3 bay leaves
6 cups water or chicken stock
1 lb chicken meat, cut into chunks
1 tablespoon file powder
1 tablespoon each paprika, garlic powder, salt, oregano, thyme, pepper (but I ended up using much, much more)

Combine oil and flour in large cast-iron Dutch oven, over medium heat. STIR CONSTANTLY AND EVENLY for 20-25 minutes, until flour/oil mixture becomes the color of chocolate. This is a dark roux. If you stop stirring, the flour will burn and you will have to start all over again. Once the roux is the proper color, add onions, celery and bell peppers and continue stirring 4-5 minutes. Add sausage, bay leaves and spices. Continue to stir 4-5 minutes. Add water or broth, stir until well combined. Bring to boil, reduce to medium-low. Cook uncovered, stirring occasionally, 1 hour. Add chicken, simmer for 2 hours. Remove, add file powder and fresh parsley. Serve over cooked white rice.