To make the pastry tip the flour into a large bowl and rub in the chilled butter using your fingertips until the mixture resembles coarse breadcrumbs. Stir in the sugar and the satsuma zest.
Spoon out 4 tbsp of the pastry mixture and set aside. Add approximately 4 tbsp of the juice from the satsumas to the main pastry mix to make a fairly soft dough, kneading gently until smooth. Wrap in cling film and chill for 30 mins.
Lightly flour a surface and roll out the pastry to a £1 coin thickness. Using a 9cm fluted cutter, stamp out 12 circles of pastry. Gently press these into individual tartlet tins, the pastry should just protrude above the tins to allow for shrinkage when cooked. Spoon the mincemeat into the pastry cases being careful not to overfill.
Sprinkle the pastry crumble mix over the mincemeat to cover lightly, top with the flaked almonds and drizzle over the stem ginger syrup. At this stage you can cover them with cling film and freeze the whole tray ready for baking.
When you're ready to bake the mince pies, heat the over to 200C/fan 180C/gas 6. Remove the cling film from the tray and bake the mince pies straight from the freezer for 25 mins until golden and cooked through. Cool on a wire rack and serve dusted with icing sugar. Bake unfrozen pies for 18-20 mins.