In a bowl, toss the beef stew meat with the flour, salt, and black pepper until evenly coated.
Heat a skillet over medium heat and brown the coated beef on all sides, working in batches if needed. Transfer the browned beef to the slow cooker.
Add the cubed potatoes, sliced carrots, and chopped onion to the slow cooker.
In a separate bowl, whisk together the beef broth, tomato paste, Worcestershire sauce, and dried thyme. Pour the mixture over the ingredients in the slow cooker.
Cover and cook on low for 8 hours, until the beef is tender and the vegetables are soft.
Stir the stew gently before serving to distribute the broth.