01 - Heat olive oil in a large skillet over medium-high heat. Season beef with salt and pepper, then sear all sides until browned. Transfer beef to the slow cooker.
02 - In the same skillet, add onion, carrots, and celery. Sauté for 3 to 4 minutes until softened. Add garlic and cook for an additional minute. Transfer vegetables to the slow cooker.
03 - Add crushed tomatoes, tomato paste, beef broth, red wine, oregano, thyme, bay leaves, and red pepper flakes to the slow cooker. Stir to combine evenly.
04 - Cover and cook on low for 8 hours or on high for 4 to 5 hours, until the beef is tender and easily shredded.
05 - Remove bay leaves. Shred the beef with two forks and stir back into the sauce. Season with salt and pepper as needed.
06 - About 45 minutes before serving, bring water or broth to a boil in a large saucepan. Gradually whisk in the cornmeal. Reduce heat to low and cook, stirring frequently, until thick and creamy, about 30 to 40 minutes.
07 - Stir in unsalted butter, grated Parmesan, and salt to taste until fully incorporated.
08 - Ladle the beef ragu generously over creamy polenta. Garnish with fresh basil or parsley and additional grated Parmesan if desired.