THAT sculptor Fernando Botero, who has an exhibition at the Marlborough Gallery, celebrated his birthday the other night with 50 friends, including Martha Stewart, at La Grenouille, which was decorated with reproductions of Botero's oversized nudes made of moss . . . THAT the 1.7-pound white truffle Nello Ballan brought back from Italy for regulars at his Madison Avenue eatery was the largest available - except for the 1.8-pound truffle that went to Pope Benedict XVI at the Vatican.
