The British pine tree has been a source of pine nuts in cooking dating back to the Middle Ages and the Romans used pine nuts in both sweet and savoury dishes. British pine nuts, however, were very different from the modern imported ones, being of a rather pungent turpentine flavour and much smaller than the Mediterranean variety. The pine nuts we now use are invariably imported and are sweet, delicately flavoured and full of protein. This is an adaptation of a tart which is steeped in history. In France, it is known as Tarte Grandmere, and in Italy Torta della Nonna, and in Britain it is occasionally called Grandmother's Tart. This is a rather self-indulgent tart - rich and sweet, designed to please grandmothers and their grandchildren.