Bring water to a boil in a medium saucepan. Add oysters and cook for 3 minutes. Remove oysters with a slotted spoon and reserve 3 cups of liquid. Set both aside. In a Dutch oven over medium heat, cook celery, green onions and onions in 1 tablespoon butter, stirring constantly until tender. Stir in 2½ cups reserved liquid, garlic, thyme, red pepper and bay leaf; bring to a boil. Stir in heavy cream, reduce heat and simmer for 5 minutes. Stir in milk and return to a simmer.

​Melt 1/4 cup butter in a small saucepan over low heat. Add flour, stirring until smooth. Cook 1 minute, stirring constantly, about 3 minutes or until smooth (mixture should be very thick).

​Gradually add flour mixture to milk mixture, stirring with a wire whisk until blended. Add oysters, salt and white pepper. Cook until thoroughly heated.

Remove from heat, discard bay leaf and serve with toasted buttered French bread or crackers.