Step 1

Preheat oven to 170C. Grease a 27cm x 18cm slice tin and line with baking paper, allowing the paper to sit higher than the tin to allow for the cake rising.

Step 2

Cream butter, sugar and 1/2 cup condensed milk until pale and creamy. Add eggs one at a time, beating well between each addition. Beat in vanilla essence.

Step 3

Sift flour. Fold in flour and the milk mixture to the condensed milk mixture in two batches gently with a fork to form a smooth batter.

Step 4

Pour into prepared tin, smoothing the top. Bake for 45 minutes until a skewer inserted into the centre comes out clean. Allow to cool.

Step 5

Place remaining condensed milk in a small saucepan with golden syrup and extra butter and stir over gentle heat for 5 minutes until thick and glossy. Allow to cool slightly then spread over cooled cake. Slice into squares and serve.