How to Make It
Combine first 11 ingredients and water to cover in a 15-qt. stockpot; cover. Bring to a boil over high heat (about 20 minutes). Uncover; boil, stirring occasionally, 30 minutes. Drain, reserving cooking liquid. Coarsely chop greens.
Combine smoked sausage and next 2 ingredients in pot with 2 cups reserved cooking liquid. Bring to a boil. Boil, stirring once, 15 minutes.
Meanwhile, cook chorizo in hot oil in a medium skillet over medium-low heat, stirring occasionally, 10 minutes or until browned. Remove with a slotted spoon; drain on paper towels, reserving 3 Tbsp. drippings in skillet.
Make a roux: Stir flour into reserved drippings with a wooden spoon, and cook over medium heat, stirring constantly, until flour is medium brown (about 15 minutes; see "Master the Art of Making Roux," page 5, as a guide). Add flour mixture to mixture in stockpot, and stir well. Add chopped greens mixture and 5 cups reserved cooking liquid. Reduce heat to medium-low; simmer, stirring occasionally, 20 minutes. Stir in salt, thyme, red pepper, and chorizo. Cook, stirring occasionally, 40 minutes. Stir in filé powder; stir vigorously. Serve over hot cooked rice.