Long drinks are usually not my preference but this one is special. I really loved how the celery bitter binds the calvados and sherry together. Perfect for a lightish aperitive.
"refreshingly savoury" indeed. We up the Calvados to 50ml and the sherry to 20ml, leaving the clery bitters drops at four and going with a reduced 100ml of tonic. We use an Amontillado which, for us, introduces a lovely faint sweet note to dance with the bitters.