mix flour & salt together in bowl
use 50g of butter & flatten remaining into slab approx 2cm thick
cut 50g butter into small pieces, add to flour & rub in
stir in lemon juice and 300ml (approx.) chilled water to make a soft elastic dough
quickly knead the dough until smooth - shape into a round
cut through half depth (+) and open out to form a star shape
roll out - keep centre 4 times as thick as flaps
place slab of butter in centre of dough and fold flaps envelope style - roll out into rectangle
fold bottom third up & top third down - keeping edges straight - then seal edges
wrap pastry in greaseproof paper - leave for 30 mins
put pastry on lightly floured surface -sealed edges at the sides
repeat rolling folding & resting sequence 5 times
shape pastry as required then leave in fridge for 30 mins before baking
brush with beaten egg before baking
bake in oven 220oC / mark 7 for approx. 15 mins - longer if filled