1. In small bowl, mix salt, crushed rosemary, and pepper.
2. Cut pork loin roast crosswise, making 8 deep pockets in fat side of roast. With hands, rub insides of pockets and surfaces of roast with rosemary mixture. Cut each pitted prune in half. Insert 4 or 5 prune halves into each pocket in roast.
3. Place prune-stuffed roast, fat side down, in 12" by 8" baking dish; cover with vented plastic wrap. Cook at medium low (30% power) 40 minutes. Turn roast fat side up, and rotate dish a half turn. Cover and cook 40 to 45 minutes until pork roast reaches 170°F. when tested with meat thermometer. (Unless using a micro wave-safe meat thermometer, thermometer should be used only outside microwave oven.) Cover roast tightly with foil and let stand 10 minutes.