"It sets the tone of the meal" - top Scots chefs on the elevation of bread and butter in restaurants

It has gone from an item forgotten on a side plate or bread basket to a celebrated course in multiple tasting menus. What has sparked the change in attitude to humble bread and butter, and how are top Scottish chefs leading the charge? Rosalind Erskine finds out why a comforting and simple staple has made it to the big time.