1. Heat olive oil in a skillet over medium heat. Brown the beef on all sides.
2. Transfer the beef to the slow cooker.
3. In the same skillet, add onions, carrots, and mushrooms. Cook until softened.
4. Add garlic and tomato paste. Cook for another minute.
5. Pour in red wine and beef broth. Bring to a simmer.
6. Transfer everything to the slow cooker. Add thyme, salt, and pepper.
7. Cook on low for 8 hours or until beef is tender.
8. Serve hot and enjoy!
Notes:
For a thicker sauce, you can mix 2 tablespoons of cornstarch with 2 tablespoons of water and add it to the slow cooker in the last 30 minutes of cooking.