Remove the butter mixture from the fridge and place it onto a well floured work surface, peeling off the parchment. Place the dough into the centre of the mixture and use the flaps of butter to fully encase the dough. Roll the mixture into a long oblong 40cm (16in) long.
Bring the top edge to the centre and then bring the bottom edge to the centre. Fold the pastry mixture in half along the join line. Wrap and place into the fridge for 30 minutes.
Remove the pastry from the fridge unwrap and place shortside closest to you onto a lightly floured work surface. Roll the pastry out again as before and repeat the folding procedure. Wrap and place in the fridge for a further 30 minutes.
Mix 50g (2oz) sugar and 2 teaspoon cinnamon together in a bowl. Remove the pastry from the fridge, unwrap it and roll the pastry out into a long oblong as before on a lightly floured work surface. Scatter with the cinnamon and sugar mixture over the pastry ensuring the you go right to the edges.
Fold as before. Roll the pastry out again, to form a 30cm (12in) square. Roll up tightly like a Swiss rol. Wrap tightly in and chill for a further 30 minutes.
Preheat the oven to 220℃ (200℃ fan)/425°F/gas mark 7. Remove the pastry from the fridge and unwrap. Trim the edges with a sharp knife to neaten. Slice into 18-24 slices.
Dust the work surface liberally with icing sugar, roll out each slice until very thin, dusting with more icing sugar if necessary. Once rolled place the biscuits on lined baking sheets.
Bake for 6 minutes. Remove from the oven, carefully turn the biscuits over and cook for a further 5 – 6 minutes, or until golden-brown. Transfer to a wire rack to cool.
Repeat with the remain slices until all the biscuits are baked.