You will want to eat this all by its self with a spoon but it is best served as a topping for cheesecake or part of braided bread.
3 tablespoons fresh lemon juice
3/4 teaspoon fresh lemon zest, finely grated
3 tablespoons sugar
1 large egg
2 tablespoons unsalted butter, cut into small pieces
Whisk together juice, zest, sugar, and egg in a 1-quart heavy saucepan. Stir in butter and cook over moderately low heat, whisking frequently, until curd is thick enough to hold marks of whisk and first bubble appears on surface, about 4 to 5 minutes. Transfer lemon curd to a bowl and chill, its surface covered with plastic wrap, until cold, at least 1 hour.