In a medium skillet, melt margarine, add onion, celery and bell pepper. Cook for approximately 20 minutes. Season crawfish with salt and cayenne pepper; add to skillet mixture, stirring well. Cook for 10 minutes then add parsley and onion tops. Keep Etouffee warm until needed to serve over catfish. Broiled Catfish: Use small sheet pan to lay out filets. Sprinkle both sides with seasonings. Dust each side of filets with flour. Heat flat-top grill or skillet to 375 . Pour melted margarine on grill or in skillet. Allow to heat, then add catfish. Cook for 4 minutes on each side. Remove catfish from skillet, top each Filet with 4 ounces Mulate's Crawfish Etouffee. Sprinkle top with green onions.
Note: Crawfish Etouffee may also be served over white rice. Shrimp can be used in place of crawfish and the catfish can be substituted with any fresh water fish.