Alternatively, cover the bowl loosely with cling film and microwave at 30 sec intervals until melted.

Leave the melted chocolate mixture to cool to room temperature.

2)Heat oven to 180C/160C fan/gas 4. Grease a 20cm square tin with butter and line with 2 long strips of folded baking paper or foil – one running top to bottom, the other left to right then line the base with a piece of baking paper.

The strips will help you lift it out later.