Mary Berry shows how to make chocolate cups using balloons as the mould on The Great British Bake Off 2014 Masterclass.

Mary dips the balloons filed with air in a bowl of melted chocolate several times to get a leaf shape. She then placed them in the fridge to set. Once set they removed from the fridge and the air removed from the balloons inserting a small pin.

Once the air has escaped, the balloon will fall away from the chocolate, leaving a mould.