Step 1

Preheat oven to 180C. Spray a 28 x 30cm rectangular cake pan with oil. Line base and 2 long sides with non-stick baking paper.

Step 2

Use an electric beater to beat the butter and caster sugar in a bowl until pale and creamy. Add vanilla and beat until combined. Add the eggs, 1 at a time, beating well after each addition. Transfer to a large bowl.

Step 3

Use a large metal spoon to fold in orange juice, sour cream and combined flour, in alternating batches, until just combined. Pour mixture into prepared pan and smooth the surface. Bake for 30-35 minutes or until golden and a skewer inserted into the centre comes out clean. Set aside to cool slightly before transferring to a wire rack to cool completely.

Step 4

To make the orange icing, use a clean electric beater to beat the butter until soft. Gradually add the icing sugar and beat until pale and creamy. Add the orange rind and orange juice and beat until just combined.

Step 5

Spread the icing over the cake and cut into pieces.