Sprinkle roast with salt and pepper. In a Dutch oven, brown roast in oil on all sides. Transfer to a 6-qt. slow cooker. Add the mushrooms, onions, broth, wine, tomato sauce, parsnips, celery, carrots, garlic, bay leaves, thyme and chili powder. Cover and cook on low for 6-8 hours or until meat is tender., Remove meat and vegetables to a serving platter; keep warm. Discard bay leaves. Skim fat from cooking juices; transfer to a small saucepan. Bring liquid to a boil. Combine cornstarch and water until smooth; gradually stir into the pan. Bring to a boil; cook and stir for 2 minutes or until thickened. Serve with mashed potatoes, meat and vegetables.