Preheat the oven to 160°C.
Beat the fat, banana, lemon juice, and rind in a food processor.
Transfer to a bowl and stir in the dried fruit and nuts or seeds.
Beat the eggs in a separate container if using.
Sieve the flours, spices, and baking powder if applicable.
Fold the eggs and flours alternately into the fruit mixture, adding brandy if desired.
Line a 20cm cake tin with greased greaseproof paper and spoon in the mixture.
Bake for approximately two hours until a skewer comes out clean.
Remove the cake from the tin and let it cool on a wire rack.
Serve immediately or store and ice later for Christmas.