This encompasses two recipes; a good all-purpose pie dough, and then the galette using the pie dough.
Foolproof Food Processor Pie Dough
Makes one 8- or 9-inch pie crust
5 TB cold unsalted butter
1-1/4 (5-5/8oz) AP (plain) flour
½ tsp salt
2 TB granulated (caster) sugar
A galette is a very easy way to make a tart or flan and of course you can make them savoury as well as sweet. This recipe is vegan as I've used shortcrust made with margarine and glazed with apricot jam to get the pastry looking golden - but you could use egg wash instead (or both)...