Pipe small rounds, about 2cm in diameter, on to the baking sheets, trimming the paste from the bag with a knife. Leave room between them to allow for spreading. You should end up with about 75 rounds. Bake for 25 minutes, in batches if necessary depending on how many baking sheets you have, until well risen and golden, rotating the baking sheets half way through cooking. As soon as the pastry is cooked, make a 1cm slit on the side of each bun to let the steam escape. (This stops them turning soggy as they cool). Return to the oven for a further 5 minutes to dry them out, then transfer to a wire rack to cool. Store in an airtight container (or freeze).