Lemon curd is a rich, tart spread made with lemons. Other citrus fruits such as limes, oranges, and tangerines can be used to create curds as well, although lemon is an enduring favorite. This spread is particularly associated with Great Britain, where it has traditionally accompanied tea since the 18th century. It can be spread on scones, toast, and other foods, and it may also be used as a filling for desserts such as cookies, tarts, and pies.
When cooks make lemon curd, they gently cook lemon juice with eggs and sugar to create a very rich custard. The custard can be made even more tart and flavorful with the addition of lemon zest, and it can also be cut for a more soft, creamy flavor with ingredients such as butter and whipped cream. When made well, it tastes like a lemon concentrate, with an intense burst of citrus flavor that many consumers greatly enjoy.
Fresh lemon curd tends to keep for only a few days, although some cooks have recipes for lemon preserves which can last for several months. Commercially produced products are made more shelf-stable with the addition of stabilizers that will prevent it from going off, although it can have a flat or metallic flavor as a result. Making fresh curd is actually quite simple, and well worth it for people planning a traditional tea, or those who want an intense lemon concentrate for desserts. Fresh curd has a clear flavor that is quite distinctive.
To make a batch, a cook will need a double boiler. Cooking the lemon juice and eggs over boiling water will prevent the eggs from clumping, which can result in unsightly chunks and specks. Those who don't have a double boiler can improvise with a heat-safe bowl suspended in a pot of simmering water.
Cooks can start by whisking three eggs together in the double boiler with 0.33 cup (78.8 ml) of lemon juice and sugar to taste. Around 0.5 cup (100 g) of sugar is usually quite suitable, although some people prefer a sweeter product with up to 0.75 of a cup (150 g). The cook should whisk this combination continually until the mixture becomes very thick, and remove it from the heat immediately. She can then stir in 1 tablespoon (6 g) of lemon zest, and add 4 tablespoons (56.8 g) of butter if she wants it to be more creamy and soft. The curd should be used immediately or chilled and used within a week or so.