Beat cream cheese and reserved butter in medium bowl with mixer until blended. Add 2 Tbsp. crushed candy; mix well. Gradually beat in remaining sugar until blended. Spoon into pastry bag fitted with piping tip; use to pipe icing onto bottoms of half the cookies, adding about 1/2 tsp. to each. Cover with remaining cookies, top sides up, to make sandwiches. Drizzle with melted chocolate; sprinkle with remaining crushed candy. Let stand until chocolate is firm.