Ingredients

　　2 large eggs, beaten lightly

　　1 stick (1/2 cup) unsalted butter, cut into bits

　　1/2 cup sugar

　　1 tablespoon freshly grated lemon zest

　　1 tablespoon freshly grated lime zest

　　2 tablespoons fresh lemon juice

　　2 tablespoons fresh lime juice

　　In a saucepan combine the eggs, the butter, the sugar, the zests, and the juices and cook the mixture over moderately low heat, whisking constantly, for 1 to 2 minutes, or until the curd is thick enough to hold the mark of the whisk and the first bubble appears on the surface. Transfer the curd to a small bowl, cover its surface with plastic wrap, and let the curd cool. Chill the curd, covered with the plastic wrap, for 1 hour and serve it with biscuits or scones or as a filling for tartlets.