HEAT oven to 350ºF.
MELT butter in large skillet on medium heat. Add apples; cook and stir 3 min. or until crisp-tender. Add water and stuffing mix; cover. Let stand 5 min.; mix lightly.
SPOON stuffing mixture onto cut-side of meat to within 1/2 inch of edge. Roll up, jelly-roll fashion, starting at one short end. Place seam-side down, in roasting pan sprayed with cooking spray.
BAKE 1 hour. Mix syrup, mustard and rosemary; spread over meat. Bake 20 min. or until meat is done (160°F). Let stand 15 min. before slicing to serve.