In a large stockpot, bring the chicken stock to a boil. Temper approximately 6 tablespoons of roux into the broth (add 1/2 cup of hot broth to the roux and mix completely. Add the broth and roux mixture back into the boiling broth and whisk). Add potato. Simmer for 12 minutes and add the onion, peppers, celery, garlic, and chicken pieces.
Add Creole seasoning. Taste and adjust seasoning, if desired. Continue to cook for another 10 minutes (the vegetables should be cooked, but still firm). Ladle 8 to12 oz. of gumbo over potatoes.
Slowly brown the flourr on a sheet pan at 300°F. Stir the mixture halfway through (about 10-15 minutes) to achieve an even browning. The flour should be a light khaki color and will smell like roasted nuts (about 20-30 minutes).
On the stovetop, cook the flour and the butter over medium-high heat until a brown, smooth consistency occurs (about 5 to 6 minutes). Once the roux has cooled, cover and leave unrefrigerated until needed. Later, if any oil has separated from the roux, simply stir the oil into the mixture.
Combine all ingredients and mix thoroughly. May be stored in a tightly covered container.