In a large skillet, heat 2 tablespoons of olive oil over medium-high heat until shimmering.
Generously season the beef cubes with salt and pepper. In batches, add the seasoned beef to the hot skillet and sear on all sides until browned, about 5-7 minutes per batch. Once browned, carefully transfer the beef to a slow cooker.
Using the same skillet, pour in the remaining 2 tablespoons of olive oil. Add the diced onions and sliced carrots to the skillet and sauté until the onions become translucent and the carrots start to soften, approximately 5 minutes. Stir in the minced garlic and cook for an additional minute until fragrant.
Transfer the sautéed vegetables to the slow cooker with the beef, ensuring an even distribution.
Pour in the beef broth, and then add the quartered mushrooms, tomato paste, dried thyme, bay leaves, and Worcestershire sauce. Season with additional salt and pepper according to your taste. Gently stir to combine all ingredients.
Cover the slow cooker with its lid and cook on low for 7-8 hours, or on high for 4-5 hours, until the beef is fork-tender and the flavors have melded together beautifully.
Before serving, remove and discard the bay leaves for a clean finish.
Notes
Serve with crusty bread or creamy mashed potatoes for a complete meal.