For the pastry: Mix together the flour, salt and caster sugar in a bowl. Then using your hands, rub in the cold butter until it resembles breadcrumbs. Slowly pour in the water and mix until it forms a rough dough. Tip out onto a lightly floured worksurface and knead briefly until a dough forms. Flatten into a disc, wrap in clingfilm and leave to chill in the fridge for 30 minutes.
Preheat the oven to 200C/180C Fan/Gas Mark 6.
For the crumble: Add the butter, sugar and flour into a bowl and rub together with your hands. You want to leave some lumps of butter intact, so you have a mixture of larger and ‘breadcrumb’ style crumbs. Then set aside.
Roll the chilled dough out, on a lightly floured work surface, until a few millimetres thick. Then using a 6cm cookie cutter, cut out 12 rounds and place into the indentations of a shallow bun tin. Then divide the mincemeat between each pastry round, spooning into the middle. Finally, top each pie with the crumble mixture.
Bake in the oven for 15-17minutes until golden brown and bubbling. Leave in the tin for 1-2 minutes, before removing and placing on a cooling rack. Eat still warm, with a sprinkling of icing sugar on top if desired!