Brown the Beef: In a skillet over medium-high heat, brown the beef cubes on all sides for about 5-7 minutes.

Sauté the Vegetables: Sauté the onions, garlic, and mushrooms in the same skillet for 3-4 minutes, then add the carrots for an additional 2 minutes.

Combine Ingredients: Transfer the seared beef and vegetables to the slow cooker, add red wine, beef broth, tomato paste, Worcestershire sauce, thyme, and bay leaf. Stir until well combined.

Slow Cook: Cover and cook on low for 8 hours or high for 4 hours until beef is fork-tender.

Serve: Discard the bay leaf, adjust seasoning if needed, and serve over mashed potatoes or bread, garnished with parsley.