In a small bowl, combine sultanas and rum and microwave for one minute until sultanas are plump and juicy. Set aside to cool.
Preheat oven to 175ºC fan bake. Line 2 x 22cm tins with baking paper.
In the bowl of an electric mixer, cream butter and sugar until pale, light and fluffy. Add vanilla and then eggs, one at a time.
In two batches add flour, ground almonds, spices and baking powder, alternating with milk. Stop mixing once combined; be careful not to over-mix.
Fold through dried fruit including rum-soaked sultanas (and any excess rum in the bowl).
Pour batter into two lined tins and spread out to the sides. Bake for about 30 minutes or until golden in colour, springy to the touch and a skewer inserted in the centre comes out clean. Allow cakes to cool for 10 minutes before turning onto a cooling rack.
Meanwhile, make icing. In the bowl of an electric mixer, beat butter and icing sugar until smooth, and then gradually add cream cheese and vanilla. The icing should be smooth, creamy and thick. Stir through rum at the end.
Once cake is cool, apply a generous amount of icing to one layer, using a palette knife to spread it out to the edges. Place other cake layer on top and ice it generously, leaving some texture in the icing.
Decorate with dried cranberries, pistachios and candied orange slice, if using. Serve at room temperature with a generous dollop of whipped cream or custard.
To store, refrigerate in an airtight container for up to 3 days.