Pre-heat oven to 180°C (160?C fan-forced). Line two 12 hole (1/3 cup/80ml) muffin tins with paper cupcake liners.
Place mixed fruit, dates, prunes, almonds, orange juice and zest in a large bowl. Add brown sugar, flours and spices and mix to combine.
Dissolve bi-carb soda into 2/3 cup (160ml) cold water and stir through pudding mixture with melted butter. Spoon cake mixture into paper liners and bake for 20 minutes or until a toothpick or skewer inserted in the middle comes out clean. Allow to cool.
For Eggnog buttercream, beat butter, icing sugar and spices until smooth. Continue to beat while gradually adding milk until mixture is a spreadable consistency.
Frost cooled cakes with Eggnog buttercream, sprinkle with extra nutmeg and serve immediately.
