In a food processor or by hand, combine flour, powdered sugar, and salt. Add cold cubed butter and pulse or cut in until crumbly. Mix in egg yolk and ice water until dough just comes together. Form into a disk, wrap in plastic, and chill 30 minutes.

Preheat oven to 350°F. Roll dough to 1/8-inch thickness on floured surface. Cut circles and press gently into 12 mini tartlet pans or muffin tin cups. Prick bottoms with fork.

Line shells with parchment or foil and fill with pie weights or dried beans. Blind bake 15-18 minutes until pale golden. Remove weights and bake 2-3 minutes more for crisp bottoms. Cool completely on wire rack.

In a medium saucepan, whisk egg yolks, granulated sugar, lemon zest, fresh lemon juice, and salt until combined.

Cook over medium-low heat, whisking constantly, until mixture thickens and coats the back of a spoon (about 8-10 minutes). Do not boil.

Remove from heat. Stir in cubed butter one piece at a time until fully melted and glossy. Strain through fine mesh sieve for ultra-smooth texture.

Spoon or pipe cooled lemon curd into cooled tartlet shells, filling nearly to the top. Smooth surfaces.

Refrigerate at least 2 hours until curd is fully set. Garnish with fresh berries and powdered sugar before serving.