Preheat oven to 350ºF. Heat 2 Tablespoons oil in Dutch oven over medium-high heat until almost smoking. Add beef in two batches; cook about 10 minutes per batch or until browned on all sides. Remove beef to a large bowl.
Add remaining 1 Tablespoon oil to Dutch oven; heat over medium heat. Add onions and celery; cook about 10 minutes or until onions are softened and translucent. Add flour, garlic, tomato paste, thyme, salt and pepper; cook and stir 1 minute. Add Guinness beer; use wooden spoon to scrape up browned bit from bottom of Dutch oven. Return beef to pan; stir in broth.
Cover and bake 1 hour. Stir in carrots, turnips and potatoes; cover and bake about 1 hour 20 minutes or until beef and vegetables are tender. Stir in parsley.