To make the pastry, sift the flour and salt into a bowl and add the orange rind. Put a grater into the bowl on top of the flour. Hold the frozen block of butter at one end in a cloth and grate off three-quarters (175 g/6 oz) of it on the coarsest blade. Using a knife, mix the butter roughly into the flour until crumbly. Then add the orange juice and cold water, mixing again with a knife. Gather up the dough in your hands and press into a ball. Wrap in cling film and refrigerate for at least an hour.
Preheat the oven to 220°C/425°F/gas mark 7. Butter two 22-23 cm/8½-9 in sandwich tins. Cut the pastry in half and shape each half into a ball. Roll out into 2 rather thick circles, big enough to fit tightly into the sandwich tins. If necessary, press in the edges to make them neater. Prick all over with a fork and bake just above the centre of the oven for 20-25 minutes, until risen and golden brown. Leave to cool in the tins.
Put one pastry circle on a serving plate. Whisk the cream until thick. Spread half the cream on the pastry circle, then pile on the raspberries sprinkled with a little caster sugar. Dollop the rest of the cream over them. Top with the second pastry circle and sprinkle the icing sugar through a fine sieve on top of this. Once assembled, serve as soon as possible.