Bring 2 1/2 cups nectar to boil; dissolve gelatin in remaining 1/2 cup nectar. Pour dissolved gelatin into boiling nectar, stirring well. Remove from stove, pour slowly over blended yolks. Chill until mixture mounds slightly when dropped from spoon. Beat egg whites until almost stiff; slowly beat in 1/4 cup sugar. Gently fold into chilled gelatin mixture and add grated rind and almond extract. Pour into cooled crust and chill several hours. Top with whipped cream.