A rich, creamy soup with chunks of chopped oysters from Chef Jeff Tunks' restaurant Acadiana.
In a food processor, chop celery, lettuce, spinach, green onions, and garlic to a fine purée. Gently heat the butter in a large saucepot and add the vegetables. Sauté in the butter over medium heat.
Meanwhile, poach the oysters in a small saucepot with enough water to cover them (about 2-3 minutes) at a simmer, until plump and edges are slightly curled.
Reserve the oysters and pour poaching liquid into the sautéed vegetables. Chop the oysters.
Stir the Herbsaint, Brie, and cream into the saucepot. Add cayenne and season to taste with salt. Cook over low heat for 15 minutes. Stir in chopped oysters and serve.