Preheat oven to 180°C (350°F)
Grease and line a 22cm (8-9inch) pan.
In a large bowl whisk the butter and sugar until light and creamy.
Add the eggs, one at a time, beating well.
Beat in the vanilla.
Add flour, baking powder, cinnamon, mixed spice, sultanas, and feijoas.
With a spatula gently mix until just combined.
Pour cake mix into prepared pan. Bake for 35 - 40 minutes or until a skewer comes out clean in the middle.
Leave to cool for around 10 minutes before transferring to a wire rack to cool.
Dust with icing sugar