Slow-Cooker Classic Pot Roast

In a 4- to 6-quart slow cooker, whisk together the tomato paste, cornstarch, and 1 cup water. Add the carrots, potatoes, onion, celery, and bay leaves and toss to combine. Season the beef with 11/2 teaspoons salt and 1/2 teaspoon pepper and set on top of the vegetables. Cover and cook until tender, on low for 7 to 8 hours or on high for 4 to 5 hours (this will shorten total recipe time). Let the meat rest for 10 minutes before discarding the kitchen twine and slicing the meat across the grain. Serve with the vegetables and cooking liquid and sprinkle with the parsley.