Step 1

Preheat oven to 180 C (350 F) standard / 160 C (320 F) fan-forced. Grease and line an 8-inch round cake pan with baking or parchment paper.

Step 2

In a large mixing bowl, add flour, baking powder, sugar and salt. In a separate bowl, add oil, vanilla and egg. Beat briefly with fork just to break up the egg yolk.

Step 3

Add to dry ingredients along with the sour cream and stir to combine. The cake batter will be very thick (see photo below) – this is ok.

Step 4

Transfer cake batter to your cake pan and gently smooth the top. Bake cake for approximately 35-40 minutes or until a skewer inserted in the middle comes out clean.

Step 5

Leave cake to cool slightly before carefully removing from cake pan and leaving on a wire rack to cool completely.

Step 6

To make the frosting, add butter to a large mixing bowl. Beat with an electric mixer on medium speed for 2 minutes or until smooth and creamy. Add vanilla and sugar and beat slowly until it starts to come together. Add sour cream and continue to beat until smooth.

Step 7

Cover top of cake with sour cream frosting and serve.