The deal is done. Cosmopolitan editor Helen Gurley Brown has officially sold her Beresford penthouse, with the apartment closing for $19.38 million. As The Real Deal reported in December, the flamboyantly pink quadruplex, long owned by the late “Sex and the Single Girl” author, went into contract after just a month on the market. The apartment stretches into one of the building’s three iconic towers at 211 Central Park West. It was asking $20 million … [more]