Lemon Curd

3/4 cup fresh lemon juice
1 tablespoon fresh lemon zest
1 cup sugar
3 large eggs
1 egg yolk
8 tablespoons unsalted butter

Directions
Whisk together lemon juice, lemon zest, sugar, and eggs in a 2-quart saucepan.

Cut butter into bits and add to mixture.

Cook mixture, stirring constantly, over moderately low heat until curd is thick enough to hold marks of whisk and first bubble appears on surface, about 10-12 minutes. Cover the surface with plastic wrap. You can make the curd 1 week ahead and chill it, covered.