Preheat oven to 160°C / 325F and line a square cake tin of 8” X 8” with parchment paper.
In a bowl, place the sultanas (raisins), boiling water and whiskey. Set aside to soak at least 30 minutes.
In a second bowl, place the cake pieces and add the milk. Leave to soak for 5-10 minutes to have a spongy dough.
Combine both bowls ingredients into one bowl and let sit while you go to next step.
In a third large bowl, combine the butter, and brown sugar. Stir together to combine well. Add one egg into the butter and sugar mixture. Mix to combine well.
Add ground ginger and mixed spices and blend well. Add the baking powder, stir, and then add the flour and stir well to combine.
Then add the soaked sultan (raisin) mixture and cake mixture to the sugar / flour mixture.
Combine with a wooden spoon until smooth and making sure the flour is fully incorporated and creates a loose batter.
Roll one piece of the pie crust to fit the base of the tray tin.
Pour the fruit mixture over the pie crust and level the mixture with the back of a spoon or a spatula.
Add the second piece of pie crust and prick the surface if needed then brush with egg wash (instructions below).
Bake for about 45-60 minutes until the pastry is cooked through.
Remove from heat and leave to cool.
Cut in squares and sprinkle with powdered sugar if desired.
Store in a tight-fitting tin for 2-3 weeks.