Roll pork tenderloin in pepper to coat. Place in flameproof roasting pan. Bake in preheated 350F oven 30-40 minutes until cooked through and internal temperature registers 160 degrees. Pour off fat in pan. Add wine. Place pan on burner over high heat; cook, scraping up browned bits, 1 minute. Add broth, cook, stirring to reduce liquid by half, 10 minutes. Remove from heat. Combine sour cream and mustard. Stir into pan. Slice pork, serve with sauce.