01 - In a food processor, pulse together flour, powdered sugar, and salt. Add cold butter and pulse until mixture resembles coarse crumbs. Add egg yolk and 1 tablespoon ice water, pulsing until dough just comes together, adding additional water 1 teaspoon at a time if needed. Turn dough onto lightly floured surface, gather into disk, wrap in plastic, and refrigerate for 30 minutes.
02 - Preheat oven to 350°F. Roll out dough to 1/8-inch thickness. Cut into circles and press into 8 mini tartlet pans. Prick bottoms with fork, line with parchment paper, and fill with baking weights. Bake for 12 minutes, remove weights and parchment, then bake 5 to 8 minutes more until golden. Cool completely.
03 - In a heatproof bowl, whisk together lemon juice, zest, sugar, and eggs. Set bowl over saucepan of simmering water, whisking constantly until mixture thickens, approximately 8 to 10 minutes. Remove from heat and whisk in butter until smooth. Strain through fine-mesh sieve into clean bowl, cover surface with plastic wrap, and refrigerate until set, at least 1 hour.
04 - Spoon or pipe lemon curd into cooled tartlet shells. Top with fresh berries, dust with powdered sugar, and garnish with mint leaves if desired. Serve chilled.