Gâteau Basque

Instructions

1. With a stand mixer, Beat butter and granulated sugar for 3 to 4 minutes, at medium speed until fluffy, stopping to scrape sides of mixing bowl. Add egg yolks and 2 eggs (about 100 grams), one at a time, beating well after each addition.
2. In another mixing bowl, whisk together flour, baking powder, and salt. Reduce mixer speed to low. Gradually add flour mixture to butter mixture, beating just until combined. Turn out dough, and shape into 2 disks. Wrap each disk in plastic wrap, and refrigerate for at least 1 hour.
3. Spray a 9-inch springform pan with baking spray with flour.
4. On a lightly floured surface, roll 1 disk of dough into a 12-inch circle. Transfer to prepared pan, pressing into bottom and up sides. Refrigerate for at least 30 minutes.
5. Pour Custard Filling into prepared crust, and refrigerate for another 30 minutes.
6. Roll remaining dough into a 12-inch circle. Place over filling, crimp edges, and trim excess dough. Refrigerate for at least 30 minutes.
7. Preheat oven to 400°F (200°C).
8. In a small bowl, whisk together 1 tablespoon (15 grams) water and remaining 1 egg (50 grams). Brush top of dough with egg wash.
9. Bake for 20 minutes. Reduce oven temperature to 350°F (180°C), and bake 25 minutes more, covering with foil to prevent excess browning, if necessary. Allow to cool completely before cutting. Just before serving, garnish with confectioners’ sugar, if desired.