Preheat oven to 180C/160C fan-forced. Grease and line a 20cm cake pan with baking paper.
Place all ingredients, except icing sugar, in a blender and blend until just smooth. Pour into prepared pan and bake for 45-50 minutes or until a skewer inserted into the centre comes out clean. Stand in pan for 10 minutes, then turn out onto a wire rack to cool completely.
Dust with icing sugar and serve.
