Ingredients:
1 pound medium-size shrimp, peeled
1/2 cup vegetable oil
1 cup bleached all-purpose flour
4 cups water, or 3 cups water and one cup shrimp stock, if available
1 cup chopped onion
1/2 cup chopped green bell pepper
1/2 cup chopped celery
1/4 teaspoon cayenne
1/2 teaspoon salt
2 tablespoons chopped parsley

Combine the oil and flour in a large heavy pot oven over medium heat.
Stirring slowly and constantly, make a roux the color of peanut butter,
15 to 20 minutes.
Add the chopped onion, bell pepper, and celery and cook,
stirring, until soft, 6 to 8 minutes.
Add the water, (or shrimp stock), and whisk to blend with the roux.
Bring to a boil, then reduce the heat to medium-low and simmer,
uncovered, for 1/2 hour.
Add the shrimp, salt and the cayenne and cook for 20 minutes.
Remove from the heat and stir in the parsley.
Serve over cooked rice.

Note: Remember that shrimp are 80% water. Before adding the shrimp
to the roux, the roux must be thick. It should be like a thick paste
before the shrimp are added. So no more water is needed. Just keep
the fire low and stir well.