Preheat oven to 180C/350F/gas 4.
Grease the baking sheet with butter.
Sift the flour, salt and spices into the large mixing bowl.
Add the butter and rub in to a fine breadcrumb consistency. You can do this in a processor, but you will need to transfer the mixture to the large mixing bowl once processed.
Stir in the sugar and lemon zest thoroughly.
Add the beaten egg mixture and the rose water (if using) and use your hands to massage the mixture into a dough ensuring that the eggs are thoroughly incorporated into the dry ingredients.
Wrap the dough in clingfilm and place in the fridge for 30 minutes.
On a lightly floured work surface, roll out the dough to 5mm thick and cut the ‘cakes’ out with the biscuit cutter.
Place on the baking sheet and make the decoration: using a comb, mark the top surface with diamonds, cutting half-way through the cake, then use a broad skewer to prick through the centre of each diamond.
Place in the preheated oven and bake for 20 minutes or until the biscuits are golden.
Remove from the oven and cool for 10 minutes before transferring them to the cooling rack. Cool completely before serving.
