Cut the chilled butter into small blocks (about 1cm in diameter).
Sieve the flour and salt into a mixing bowl. (If making the sweet shortcrust pastry then add your sugar with the flour and salt).
Add the butter and, using your fingertips, rub the butter into the flour mixture until it looks like fine breadcrumbs. If the butter starts to melt then chill your mixture or run your hands under cold water before continuing.
Mix in the beaten eggs and combine with the flour mixture until it forms a stiff dough. You may need to add in some of the water at this stage if the mixture is too dry. Do not overwork the mixture.
Wrap in cling film and rest in the refrigerator for a minimum of 1 hour.
Preheat oven to 200°C (400° F).
Using a floured surface roll the pastry out and place in your desired tin, easing in gently. Try not to overstretch the pastry as this will cause the pastry shell to shrink when baking.
Neaten the edge by running a knife round the top edge to remove excess pastry. With a fork, poke several small holes in the bottom of the dough.
Bake blind (see notes above) for approximately 15 minutes. Then remove baking beans and paper from pastry shell.
Return to oven for a further 10 minutes until nicely golden and crisp.
Your pastry case is now ready for filling or can be frozen at this point to be used at a later date.