Preheat the oven to 180ºC (160 fan) and grease and line a 2lb loaf tin.
Cut up the raspberries and dried cranberries in to large chunks and in a bowl and mix them in with the 4 tablespoons of Prosecco to soak while you make the rest of the cake.
Cream the butter and sugar together until light and fluffy.
Add the eggs and Prosecco and mix in well.
Drain off the fruit and add the fruit into the mix.
Sieve in the flour, baking powder and spices.
Mix altogether and put the mix into the loaf tin.
Bake for 25-35 minutes until golden brown. Use a cake tester to make sure it's cooked.
Allow to cool before decorating.
Mix up the icing powder with the Prosecco a little a time to get a smooth, medium thick icing.
When the cake is cool put the icing into a piping bag and drizzle it across the cake.
Decorate with dried cranberries and raspberries.