Preheat your oven to 350°F (175°C).

In a large bowl, combine the flour, cold butter, and sugar for the crust. Use a pastry cutter or your fingers to mix until the mixture resembles coarse crumbs.

Add the egg yolk and ice water to the flour mixture, mixing until the dough just comes together. Form the dough into a ball, wrap it in plastic wrap, and chill for 30 minutes.

Roll out the chilled dough on a lightly floured surface to fit a 9-inch tart pan. Press the dough into the pan and trim the edges. Prick the bottom with a fork all over.

Blind bake the crust by covering it with parchment paper and filling it with pie weights or dried beans. Bake for 15 minutes, then remove the weights and parchment paper and bake for another 5 minutes or until the crust is lightly golden.

For the filling, whisk together the lemon juice, lemon zest, sugar, and eggs in a medium saucepan over medium heat. Continue whisking until the mixture thickens and coats the back of a spoon.

Remove from heat and add the cubed butter, stirring until the butter is fully melted and the mixture is smooth.

Pour the lemon filling into the baked crust and smooth the top with a spatula.

Chill the tart in the refrigerator for at least 2 hours before serving to allow the filling to set.

Slice and enjoy your Perfect French Lemon Tart!