Lemon curd

3/4 cup fresh lemon juice
1 tablespoon finely grated fresh lemon zest
3/4 cup granulated sugar
1 stick (1/2 cup) unsalted butter, cut into bits
2 tablespoons cornstarch
1/2 teaspoon salt
4 large egg yolks

Simmer lemon juice, zest, sugar, butter, cornstarch, and salt in a 2-quart heavy saucepan over moderately high heat, whisking constantly, 1 minute. Lightly beat yolks in a small bowl, then add 1/4 cup lemon mixture, whisking. Add yolk mixture to remaining lemon mixture, then reduce heat to low and cook, whisking constantly, until curd is thick enough to hold marks of whisk, about 2 minutes. Transfer to a bowl, then cover surface with plastic wrap and chill.

*Subtle, tart, delicious. I like it on scones, too.