Heat the olive oil in a skillet over medium-high heat. Add the beef stew meat and brown on all sides for about 5 minutes. Transfer the meat to the slow cooker.
Add the sliced wild mushrooms, diced onion, sliced carrots, and minced garlic to the slow cooker.
Pour in the beef broth and Worcestershire sauce. Stir in the dried thyme, bay leaves, salt, and black pepper.
Cover and cook on low for 7 to 8 hours or on high for 4 hours, until the beef is very tender.
Remove the bay leaves. Ladle the soup into bowls and sprinkle with chopped fresh parsley before serving.