Place flour, powdered sugar, and salt in a food processor and pulse to combine. Add the cubed butter and pulse 4-5 times until it forms a coarse meal. Add the egg yolk and water 1 tablespoon at a time, pulsing after each addition.
Place the dough between two pieces of parchment paper (or on a lightly floured surface) and roll into a 12 inch circle. Transfer the dough into a 10 inch tart pan, press the dough into the sides and trim the excess crust. Using a fork prick the bottom of the crust. Chill the crust for 30 minutes.
Preheat the oven to 350 degrees. Line the tart dough with parchment paper and weigh down with pie weights or dried beans. Bake for 20 minutes, remove the pie weights and parchment paper and bake for an additional 10 minutes or until the crust is lightly golden. Remove from the oven and prepare the lemon curd.
Combine lemon juice, zest, sugar and salt in a saucepan and bring to a simmer over medium low heat.
In a medium bowl whisk together the eggs and egg yolks. Add 1/4 cup of the warm lemon mixture to the eggs and whisk to thoroughly combine.
Add the lemon-egg mixture to the pan and whisk thoroughly. Cook for 3-4 minutes or until the mixture has thickened. Stir in the butter until it has melted and everything is thoroughly combined.
Strain the lemon curd using a fine mesh strainer. Pour the strained lemon curd into the tart shell and smooth it out with an offset spatula. Bake the tart for 10 minutes then chill for at least 2 hours or until set. Serve as desired.