Step 1

Preheat oven to 180°C. Grease a 27cm x 17cm brownie pan and line the sides with baking paper.

Step 2

Beat butter, oil, eggs and sugar until thick and creamy. Sift in flour and cinnamon and mix until combined. Fold through apple.

Step 3

Spoon into prepared cake tin and smooth top. Bake for 35-40 minutes or until an inserted skewer comes out clean. Cool in the tin.

Step 4

For frosting, beat sour cream and icing sugar in a bowl. Spread over cooled cake and sprinkle over cinnamon sugar.