Heat the olive oil in a skillet over medium heat. Add the beef stew meat and brown it on all sides for about 5 minutes. Transfer the meat to the slow cooker.
Sprinkle the flour over the beef in the slow cooker and stir to coat. Add the beef broth, garlic, salt, and black pepper.
Place the potatoes, carrots, and pearl onions on top of the beef mixture. Lay the rosemary sprigs across the top.
Cover and cook on low for 7 to 8 hours, until the beef is tender and the vegetables are soft.
Remove the rosemary sprigs before serving. Stir the stew gently to distribute the gravy.