Add the beef stew meat, potatoes, carrots, onion, and garlic to the slow cooker.
In a small bowl, whisk the flour with about half a cup of the beef broth until smooth. Stir in the tomato paste, thyme, salt, and pepper.
Pour the remaining broth and the flour mixture into the slow cooker. Stir to combine everything.
Place the bay leaves on top. Cover and cook on low for 8 hours.
Remove the bay leaves before serving. Stir the stew to check the consistency.