01 - In a bowl, mix together flour, powdered sugar, and salt. Incorporate cold butter using fingertips or a pastry cutter until mixture resembles fine breadcrumbs.
02 - Add egg yolk and 1 tablespoon cold water, mixing gently until dough begins to come together. Add more water if necessary.
03 - Shape dough into a disk, wrap in plastic, and refrigerate for at least 20 minutes.
04 - Preheat oven to 350°F. Roll chilled dough on lightly floured surface to 1/8 inch thickness.
05 - Cut dough into 3-inch circles and gently press into tartlet pans. Trim excess and prick bottoms with a fork.
06 - Line shells with parchment and fill with baking weights. Bake for 12 minutes, then remove weights and parchment and bake an additional 8 minutes until lightly golden. Cool completely.
07 - Whisk eggs, sugar, lemon juice, and zest in a heatproof bowl set over simmering water. Stir constantly until thickened, approximately 8 to 10 minutes.
08 - Remove from heat and whisk in cubed butter until smooth. Allow to cool for 10 minutes.
09 - Spoon or pipe lemon curd into cooled tartlet shells.
10 - Refrigerate filled tartlets for at least 30 minutes. Garnish as desired before serving.