In a mixing bowl, blend together all-purpose flour, sugar, and a pinch of salt. Cut in cold butter until mixture resembles coarse sand.

Stir in the egg yolk and cold water gradually, mixing until a cohesive dough forms. Wrap the dough in plastic wrap and chill in the refrigerator for 20–30 minutes.

Preheat your oven to 350°F (175°C). Remove the dough from the refrigerator and roll it out onto a floured surface until it’s about 1/4 inch thick.

Transfer the dough to a 9-inch pie pan, trimming any excess. Prick the bottom with a fork and bake for 12–15 minutes until lightly golden. Set aside to cool slightly.

In a medium saucepan, whisk together sugar, cornstarch, lemon zest, and egg yolks until smooth. Gradually stir in the milk, ensuring no lumps remain.

Cook the mixture, constantly stirring, until it thickens and begins to bubble, about 5–7 minutes. Remove from heat and mix in fresh lemon juice, butter, and vanilla extract.

Pour the lemon custard filling into the cooled crust, smoothing the top with a spatula. Bake for 25–30 minutes, or until edges set but center jiggles slightly.

Allow to cool to room temperature. Once cooled, slice into squares or wedges and dust the top with powdered sugar. Serve and enjoy!