01 - Heat olive oil in a large skillet over medium-high heat. Season beef with salt and pepper, then sear on all sides until browned. Transfer beef to the slow cooker.
02 - In the same skillet, add onion, carrots, and celery. Sauté for 3-4 minutes until softened. Add garlic and cook for 1 more 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 all ingredients.
04 - Cover and cook on low for 8 hours or on high for 4-5 hours, until beef is fork-tender.
05 - Remove bay leaves. Shred the beef with two forks and stir it back into the sauce. Adjust salt and pepper to taste.
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, approximately 30-40 minutes.
07 - Stir in unsalted butter, grated Parmesan cheese, and salt to taste.
08 - Ladle the beef ragu generously over creamy polenta. Garnish with fresh herbs and extra Parmesan if desired.