1.Blend or process nuts, butter, liqueur and rind to a coarse paste.
2.Sprinkle board with half the sugar; place one sheet of pastry on the sugar. Roll pastry gently into sugar. Spread half the nut mixture over pastry and fold two opposite sides of pastry inwards to meet in the middle. Flatten folded pastry slightly, then brush with a little egg. Fold each side in half to meet in the middle; flatten slightly. Fold the two sides in half again so they touch in the middle. Repeat process with remaining sugar, pastry, nut mixture and egg. Cover pastry rolls, refrigerate 30 minutes.
3.Preheat oven to 180°C. Grease two oven trays.
4.Cut pastry rolls into 1cm slices; place slices about 2.5cm apart on trays.
5.Bake palmiers about 12 minutes. Transfer to wire racks to cool.
6.Meanwhile, to make orange glacé icing, sift icing sugar into a small heatproof bowl. Stir in butter, rind, juice and enough of the water to make a thick paste. Place bowl over small saucepan of simmering water; stir until icing is spreadable.
7.Spread one side of each palmier with icing; set at room temperature.