Beat together: cream cheese, 1/2 C. of brown sugar, salt & vanilla until smooth. Stir in egg yolks and chocolate. In a small bowl, beat egg whites until they peak. Add 1/4 C. brown sugar and beat til stiff & glossy. Fold into chocolate mixture. Whip the cream and add to chocolate mixture. Pour into 1 graham cracker crust. Chill for several hours.