Preheat oven to 350 degrees. Fit a homemade or store-bought pie crust into a 9-inch pie plate; line crust with parchment paper and fill with dried beans or pie weights. Bake until crust is lightly browned, about 45 minutes. Carefully lift and remove paper with pie weights and let crust cool.

In a medium saucepan, off heat, whisk together sugar, zest, and egg yolks; whisk in lemon juice and salt.

Add butter and place pan over medium-high. Cook, whisking constantly, until butter has melted, mixture is thick enough to coat the back of a spoon, and small bubbles form around the edge of pan, about 5 minutes (do not boil).

Do not chill curd; pour directly into cooled crust and smooth top. Refrigerate until chilled and set, 3 hours (or up to 1 day).