Lemon Curd

Have ready a fine-mesh strainer suspended over a medium bowl.

In a small heavy saucepan, whisk the yolks, sugar, and butter until well blended. Whisk in the lemon juice and salt. Cook over medium-low heat, stirring constantly with a silicone spatula and scraping the sides of the pan as needed, until thickened and resembling hollandaise sauce, which thickly coats the spatula but is still