1. Prepare the Crust:

1. In a food processor, combine flour, sugar, salt, and cold butter. Pulse until mixture resembles coarse crumbs.
2. Add egg and vanilla extract, then pulse until dough comes together. Wrap in plastic and chill for 30 minutes.
3. For the custard, heat milk in a saucepan until steaming. Whisk egg yolks, sugar, cornstarch, vanilla, and lemon zest in a bowl.
4. Gradually whisk hot milk into egg mixture, then return to saucepan. Cook over medium heat, stirring constantly, until thickened. Cool slightly.
5. Roll out 2/3 of the dough and line a tart pan. Pour in custard and sprinkle with pine nuts.
6. Roll remaining dough, cut into strips, and arrange lattice-style over the filling. Bake at 350°F (175°C) for 30-35 minutes until golden.
7. Cool completely, then dust with powdered sugar before serving.