I could eat lemon curd by the spoonful. It is that good. Made with Meyer lemons, it is sublime. Though I like it on a scone with a bit of clotted cream, I like it best in a tart, as a cake filling, or best of all, in a nest of billowy meringue. Over the years I have tried many recipes for lemon curd. Some call for using whole eggs, some for a combination of whole eggs and yolks, and some for yolks only. I prefer the yolk-only, which produces a rich, creamy consistency and flavor. To ensure that your lemon curd is as creamy as can be, use a vegetable peeler to zest the lemons, rather than a micro-planer or grater. The zest gets completely strained out when it is done, making the smoothest curd possible.
Making lemon curd is not difficult, but you have to be careful. Most important, make sure the mixture never boils. If it does, it will curdle, leaving you with something that tastes (and looks like) sweet, lemony, scrambled eggs. Be sure to stir the mixture evenly and constantly. It is more likely to curdle if allowed to settle in one spot for too long. The curd is done when it coats the back of a wooden spoon.