This recipe was given to me by Mary Flahavan. I liked it so much that we now make it up in batches and keep them in Kilner jars in our rooms for guests in case they're feeling a bit peckish after a long journey but don't want to ruin their dinner!
To make your own balsamic syrup bring the contents of a bottle to the boil and simmer until reduced by half, then leave to cool. We store ours in small squeezy bottles for convenience. I love to use it as it intensifies the flavour of the vinegar, making it thick and syrupy so it looks great when drizzled onto a plate.