Slow Cooker Pot Roast

In the bottom of a slow cooker, whisk together broth, tomato paste, Worcestershire, and cornstarch. Add potatoes, carrots, onion, garlic, and rosemary. Season beef with salt and pepper, then nestle into vegetables. Cover and cook on high until roast is fork-tender, 5 hours (or 8 hours on low). Thinly slice roast and arrange on top of vegetables on a platter. Skim fat from extra juices in slow cooker and drizzle over top. Serve warm.