Teisen Cnau Cyll Gwent (Gwent Hazelnut Sandwich)

"From a Welsh cake recipe collection purchased in Wales in 1992. The description says: On a farm near Chepstow in 1796, Anne Hughes, the farmer's wife, wrote a diary of the year's day-to-day events of which she was the loving, practical hub. The diary includes many recipes, all imprecise in our present-day terms but capable of interpretation. Attributed to Cousin Floe, this rich hazelnut sponge recipe was intended to be cut up "in diverse shapes", but to any mind it is better left whole. The toasted hazelnuts are what makes the cake special...."