Cut roast into ¼-inch-thick slices. In a large shallow bowl, stir together flour and 1 tablespoon Creole seasoning. Place beef slices in flour mixture, turning to coat.
In a large skillet, heat 2 tablespoons oil over medium-high heat. Working in batches, brown beef on both sides, about 2 minutes per side. Place browned beef in a 5- to 6-quart slow cooker.
Add remaining 1 tablespoon oil to skillet. Add onion, celery, bell pepper, and garlic; cook, stirring frequently, until softened, about 5 minutes. Add onion mixture to slow cooker. Add tomatoes, consommé, vinegar, Worcestershire, bay leaves, Italian seasoning, and remaining 1 tablespoon Creole seasoning to slow cooker.
Cover and cook on high until beef is tender, about 4 hours. Serve over Cheese Grits. Garnish with parsley, if desired.
Recipe by Taste of the South at https://tasteofthesouthmagazine.com/slow-cooker-grillades/