What Is Rich Shortcrust Pastry?

Rich shortcrust pastry is, as its name would suggest, a richer pastry because unlike traditional shortcrust pastry it has an egg added, as well as sugar (albeit only a teaspoon or so).
So for rich shortcrust pastry  you would take 8 oz of flour, 4 oz of butter or margarine and rub the butter into the flour until it looks like breadcrumbs.  Stir in 1 teaspoon of sugar.  Then add one egg (free range is best) add some water, enough to turn the mixture into a dough and chill it for 30 minutes.  
After this roll out to the desired width and use as you would ordinary shortcrust pastry.
Realistically, shortcrust pastry is rich enough not to have to have egg and sugar added.  Pastry is already almost 50% fat, so the egg and sugar make it even 'naughtier'.  However, some people like to use this recipe for mince pies at Christmas, viewing it as a real luxury !