Once a year—typically in the early summer, then occasionally again at the start of the fall—Welsh sheep farmers enlist the help of shearers and farmhands to help them for a special occasion: Shearing Day. In the midst of an arduous day of shearing sheep, the workers are rewarded with cups of tea, a spread of food, and cake. Shearing cake, or cacen gneifo (pronounced “c-ack-en guh-nigh-fo”) in Welsh, was traditionally made to celebrate Shearing Day. A simple, buttery sponge, the cake was studded with heady caraway seed, lemon rind, and…