Can the Custard Cream Hearts cookie recipe be doubled successfully or is it better to make separate batches?
Nigella's Custard Cream Hearts (from FEAST) are her home-made version of a classic British sandwich biscuit. The cookies are cut into hearts, rather than rectangles, and would be a wonderful treat for Valentine's Day.
You could make a double batch of the dough, though it really depends on the capacity of the food processor as you don't want to process the dough for too long. It may be easier to make one batch and then a second batch (no need to wash the processor in between each batch). If you do make a double batch then split the dough into two balls to wrap and chill it as one large ball will take much longer to chill and it will be more difficult to roll out a large quantity. The buttercream filling can easily be made as a double batch in the food processor.