Ingredients
300g plain flour plus extra for dusting 
½ tsp salt 
100g cold butter, cut into cubes 
200g butter, frozen 
125ml ice cold water

Method
Put the flour and salt in a bowl and with your hands mix. Put the cold butter cubes into the flour and rub the butter into the flour using your fingers until the mixture resembles breadcrumbs. Add 4 tbsps water initially and start to form a dough.  If the dough doesn’t come together fully then add an additional tbsp or so of water, 1 tbsp at a time. You want the dough to just come together and not be wet so it may well be you won’t need all of the water.  

Roll the dough out into a rectangle on a lightly floured work surface. And grate half of the frozen butter over the bottom two thirds of the dough. Fold down the top third and fold up the bottom third as if folding a letter.

Turn the folded dough 90° so the open seams are now horizontal to you rather than vertical and roll it out into a rectangle again. Grate the remaining frozen butter over the bottom two thirds of the dough. Fold down the top third and fold up the bottom third.  Lightly press your finger into the bottom right-hand corner of the dough to make a slight indentation, this shows how the dough was positioned on the board before which is important for the next folding step.

Wrap the dough in cling film and leave to rest in the fridge for at least 30 minutes.

Remove the dough from the clingfilm and place it on your work surface with the indent in the same position as it was before at the bottom right-hand corner. Next, turn the dough 90° clockwise again and fold the top third down, bottom third up and turn. Fold again then put an indentation in the bottom right cover and refrigerate. Repeat twice more, ensuring you end on the final rest.