01 - Pat beef dry and season with salt and freshly ground black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Brown beef on all sides, about 4 to 5 minutes per batch. Transfer to slow cooker.
03 - In the same skillet, add onion, carrots, celery, and garlic. Sauté for 4 to 5 minutes until softened. Transfer to slow cooker.
04 - Add crushed tomatoes, tomato paste, beef broth, red wine, dried oregano, dried thyme, bay leaves, and red pepper flakes to the slow cooker. Stir to combine.
05 - Cover and cook on low for 8 hours or on high for 4 to 5 hours until beef is fork-tender.
06 - Remove bay leaves. Shred beef using two forks, stir well, and adjust seasoning with salt and pepper.
07 - About 30 minutes before serving, bring water or broth to a boil in a large saucepan. Gradually whisk in the polenta. Reduce heat to low and cook, stirring frequently, for 20 to 25 minutes until thick and creamy.
08 - Stir in butter, Parmesan cheese, and salt to taste.
09 - Ladle creamy polenta into bowls, top with beef ragu. Garnish with chopped parsley and additional Parmesan cheese.