Pare, core and slice 1 pear; saute in 4 tb. butter or margarine for abt. 10 min. Puree in food processor or blender with yams, orange peel, cinnamon and salt. Halve and core the remaining 3 pears. Place pears, cut side up, in a buttered shallow baking dish. Pipe about 1/4 cup yam mixture into center of each pear healf, using a pastry bag with large star tip. Dot each with about 1 tsp. butter or margarine. Sprinkle each with 1 tsp. brown sugar. Bake, uncovered, in preheated 350 F. oven for about 30 minutes or until pears are tender. Serve as dessert or as a side dish with roast beef or pork. NOTE: Yam mixture may be mounded into the center of pear halves with a soup spoon or ice cream scoop.