Gâteau Basque

Step 1

In a medium bowl, whisk together the flour, baking powder and salt.

Step 2

Working with a mixer (use a paddle attachment if you have one), beat together the butter and both sugars on medium speed until smooth, about 3 minutes. Add the egg, and beat for another 2 minutes, scraping the bowl as needed. Beat in the vanilla; the mixture should be smooth. Add the flour mixture all at once, then pulse the mixer to begin incorporating it. Mix on low until blended.

Step 3

Turn the dough out onto a work surface, gather into a ball, then divide in half.

Step 4

Shape each piece into a disk — the dough will be sticky — and put each between sheets of parchment paper. Using a rolling pin, roll each piece into a round just a smidge wider than 8 inches. Keeping the dough sandwiched between the parchment, refrigerate for at least 3 hours (or for up to 3 days).

Step 5

When you’re ready to bake, center a rack in the oven, and heat to 350 degrees. Generously butter an 8-inch-by-2-inch round cake pan. Remove the dough from the fridge, and leave on the counter until pliable, about 10 minutes. Peel away the paper.

Step 6

Fit one round into the pan; if it breaks, just press the pieces together. Either fold the extra dough over and onto the base or trim it; don’t fuss about precision here. Spread about 3/4 cup of the jam over the base, leaving a 1-inch border bare and adding more jam, if needed.

Step 7

Top with the second piece of dough, lightly pressing down around the edges and, if you can, tucking the dough under a bit. Again, it doesn’t have to be perfect; the dough is soft, and as if by magic, the layers fuse in the oven.

Step 8

Brush the top with the egg wash, and use the tines of a fork to etch a crosshatch pattern.

Step 9

Bake the cake for 40 to 45 minutes, or until the top is golden brown. Transfer to a rack, and let rest for 5 minutes, then carefully run a table knife around the edge of the cake. Unmold onto the rack, and then quickly and carefully turn the cake over onto another rack, crosshatch side up, so that it can cool to room temperature. Wrapped well, the cake will keep for 2 days at room temperature.