Scotland has a long tradition of smoking both haddock and salmon. In medieval times, special smokehouses small narrow buildings with wooden beams - dotted the countryside, although in Scotland's fishing districts, it was common for fishermen's wives to smoke their fish in their own chimneys, using peat as a fuel instead of the oak and ash preferred further south. The addition of cooked cucumber revives a tradition dating back to the sixteenth century, when English cucumbers were regarded, like courgettes, as prime targets for stuffing and baking, as well as pickling (gherkins). They have an age-old affinity with salmon. Long regarded as a luxury food and a Christmas treat, smoked salmon is now enjoying all-year-round popularity and this tart is guaranteed not to fail.