1) Line a 23cm round cake tin with greaseproof paper and set aside. Position the oven rack to just below the centre of the oven so that when the cake is in the oven it will be central. Preheat the oven to 150C/Gas 2.
2) In the bowl of an electric mixer, cream together the butter, sugar, and treacle until the mixture is light and fluffy and pale in color. Beat in the eggs, 1 at a time, adding 1 tablespoon of flour along with each egg, to help prevent the mixture from curdling. Add 6 eggs and then check the consistency of the batter; it should be a "dropping" consistency, which means that if you lift a spoonful of the mixture out of the bowl and turn the spoon over, the mixture should drop off the spoon in 2 to 3 seconds. Add more eggs, 1 at a time, until the batter reaches a "dropping" consistency is reached.
3) In a separate large bowl, mix the remaining flour with all of the remaining ingredients, except the brandy. Add the flour mixture to the creamed mixture and beat until just incorporated. Spoon batter into the prepared cake tin, and level the surface.
4) Bake in the centre of the oven for 3 to 3 1/2 hours. As cooking times can vary considerably in different ovens, check the cake regularly, covering the top with a sheet of greaseproof paper if the cake starts to brown too quickly; begin checking for doneness after 1 1/2 hours. To test if the cake is cooked, insert a skewer and then remove it; if it comes out clean then the cake is cooked; otherwise bake for a little longer. Also listen to the cake; if you can still hear it bubbling then it isn't cooked through.
5) Remove the cake from the oven and let it cool in the pan for about 30 minutes. Then spoon the brandy on top. Set aside until completely cooled. Remove the cake from the pan and then wrap it in greaseproof paper and then aluminium foil before storing it in a cool, dry place.
6) The cake may be eaten immediately but is best left about a month before decorating so that it has time to "mature."