Put the dried fruit in a bowl and pour the brandy over top. Stir to mix and cover with some Saran wrap or cling film. Leave for at least 30 minutes or up to 12 hours, stirring occasionally, so the alcohol can soak into the fruit.
Preheat the oven to 325°F (160°C). Lightly grease a 13 x 9 inch pan with butter.
Sift together the flour, baking powder, salt, cinnamon, ginger and nutmeg. Set aside.
Cream the butter or sugar in the bowl of an electric mixer until light and fluffy. Beat in the eggs, one at a time, scraping down the bowl with a spatula and beating well after each addition.
Beat in the flour and spice mixture, a little at a time.
Add the mincemeat and mix until combined.
Remove the bowl from the electric mixer and use a wooden spoon to fold in the mixed dried fruit, along with any remaining brandy in the bowl.
Put the batter in the prepared pan, spreading it out to the edges with a spatula. It may look like there isn't enough batter to fill the pan, but if you coax the batter to the edges of the pan it fills it nicely.
Mix the topping ingredients together and sprinkle over the batter.
Bake for 25 to 35 minutes or until a skewer inserted in the centre of the cake comes out clean.
Cool on a rack for 15 minutes before carefully removing from the pan. Allow to cool completely before glazing.
To make the glaze, add the water to the icing sugar a little at a time, until a smooth, pourable consistency is reached.
Drizzle the glaze over the cake.
Allow the glaze to set before cutting into squares to serve.