Key Lime Tart

Instructions

1. Sift together the flour, confectioners’ sugar, and salt into a bowl.
2. Add the cold cubed butter and rub it into the flour mixture with your fingertips or a pastry cutter until it resembles coarse crumbs with pea-sized bits of butter remaining.
3. Mix in the egg yolk and ice water, combining quickly to form a dough. Avoid overworking. Shape into a flattened disk, wrap tightly in plastic wrap, and chill for at least 60 minutes.
4. Preheat the oven to 375°F (190°C). On a lightly floured surface, roll out the dough into a 12-inch circle. Gently transfer it to a 9-inch tart pan with a removable bottom. Press the dough evenly against the bottom and sides. Trim excess dough.
5. Prick the bottom of the crust all over with a fork. Line the crust with parchment paper or foil and fill with pie weights or dried beans.
6. Bake the crust for 15 minutes. Remove weights and parchment, then bake another 8 to 10 minutes until golden and set. Let cool slightly.
7. Reduce oven temperature to 325°F (160°C). In a medium heatproof bowl, whisk together the eggs, sugar, and vanilla bean paste until smooth.
8. Stir in the fresh key lime juice. Place the bowl over a saucepan of simmering water (double boiler) and cook, stirring constantly, until the mixture thickens and reaches 170°F (77°C) on a candy thermometer, about 6–8 minutes.
9. Remove from heat and whisk in the butter pieces until melted and fully incorporated, creating a smooth custard.
10. Pour the filling into the baked crust and smooth the top with a spatula.
11. Bake the tart at 325°F (160°C) for 15 minutes, or until the filling is just set with a slight jiggle in the center.
12. Remove from oven and cool to room temperature, then chill in the refrigerator for at least 1 hour before serving.
13. To serve, carefully remove the tart from the pan and slice with a sharp knife.