Gateau Basque

25 steps

1. Start by making a "pate sablee" (this is almost like a shortcrust ... but not quite)
2. Cut up 200g of cold butter in small dice, and hand mix in a bowl with 200g of sugar
3. Once the sugar and butter are loosely incorporated (but not creamed), add 300g of all-purpose flour, 4g of salt, and 8g of baking powder. Mix with your hands, lightly rubbing the dough between your fingers - the goal here is to end up with a coarse, grainy mix, almost the texture of sand.
4. Once the butter and dry ingredients are mixed, add 5 egg yolks and 1 egg white, along with the zest of 1 lemon. Mix the ingredients by "cutting" the dough repeatedly in the mixing bowl with a silicone spatula. This is to incorporate the egg yolks without raising the temperature of the mix so that the butter crumbles don't start to melt. Stop mixing when the dough becomes homogenous and slightly "sweaty".
5. Gather up the dough in one big ball. Spread some flour on a smooth surface, and knead the dough by squishing the ball down onto the surface with the palm of one hand, then gathering up the resulting mess into a ball and repeating. Repeat that process a half dozen times or more, until the dough is uniformly kneaded. Be careful not to overwork it though, or your crust will lose its flakiness.
6. Separate the dough into two balls of equal weight - one will be for the bottom crust of the gateau, the other one will be used to cover the top. Lay down a piece of parchment paper, and use a rolling pin to lightly spread one of the dough balls to form a thick round "palet" about 6 inches across. Cover up with a piece of saran wrap, and store in the freezer for 10 minutes. Repeat the same process with the other half of the dough.
7. Once the dough balls are cold, repeat the rolling process enough times to yield two flattened dough circles, about 3 millimeters thick. Pro tip: rolling out the dough while cold and still trapped in between the parchment paper and saran wrap will help avoid any dough sticking to the rolling pin. Once done, put the dough disks back in the freezer for at least 10 minutes.
8. Butter and flour a 9-inch round cake pan (the one with the higher sides).
9. Use one of the rolled-out dough disks to line the cake pan. Pro tip: this is easiest if the dough is still very cold (almost frozen) - this dough gets unwieldy when it gets to room temperature! Once the dough is in the cake pan, cut the excess off the sides, and put the cake pan (and dough) back in the freezer while you work on the filling.
10. For the filling, start by bringing 500 milliliters of milk, 2 teaspoons of vanilla extract (or seeds from two vanilla beans), and 25g sugar *almost* to a boil (about 200F), for about 3 to 5 minutes.
11. While the milk is heating up, use a large bowl to mix 6 egg yolks, one egg white, and the rest of the sugar (75g).
12. Once the milk temperature is back to below 185 F, pour about of half cup of the hot milk into the egg mixture, and whisk vigorously. This will temper the eggs, and raise their temperature enough so they don't immediately turn into scrambled eggs in the next step.
13. As soon as the eggs are tempered, pour the egg mixture into the hot milk, and very slowly heat up on the stove while constantly whisking. Eventually, the eggs and milk will thicken to form a custard. NOTE: it is very easy to go too fast or too hot here, which will completely bypass the custard stage and leave you with vanilla-flavored scrambled eggs... Highly recommend using a cooking thermometer to ensure that you never go above 180 F (the custard reaction happens between 167 F and 176 F)
14. As soon as your egg and milk mixture starts to thicken (you'll feel it), turn off the heat. Continue whisking while the mixture cools down a little, then transfer to a Kitchen Aid with a whisk attachment. Set the Kitchen Aid to a low / medium whisking speed, and add the rest of the ingedients (per below).
15. While your custard is in the mixer, add 40g of corn starch, 20g of flour, 20g of butter, 2 drops of almond extract, and 20g of almond meal. You now have a delicious "creme patissiere aux amandes".
16. Once your creme patissiere is well mixed, remove the mixing bowl and cover the creme patissiere with saran wrap, completely covering the mixture all the way to the sides of the bowl. The goal is to protect the creme patissiere from air contact while it cools down, so the saran wrap should be touching the creme and tucked on the sides of the bowl.
17. Set the bowl of creme patissiere in the fridge for at least one or two hours (best overnight) so it can cool down and start to set.
18. Once the creme patissiere is cooled, place it in the cake pan and smooth out the top. Pro tip: it's easiest to use a piping bag to ensure the creme patissiere is distributed evenly in the cake pan.
19. OPTIONAL: if you want, ou can spread a generous amount of cherry preserves in the bottom of the cake pan before layering the creme patissiere on top. This is the traditional way that gateau basque is made, but it's just as delicious without the fruit jam.
20. Take out the remaining frozen dough disk, and brush about one inch of the outer rim with an egg wash (one egg yolk + a tablespoon of cold water). This will allow the top layer of dough to "stick" to the sides of the dough in the cake pan. Keep the rest of the egg wash - you'll need it in a bit.
21. Flip your dough disk so that the egg-washed side is facing down, and place it on top of the cake pan filled with creme patissiere. Work the sides of the dough lightly to ensure they are connected, and none of the filling can escape during baking. You will likely have more dough on the sides of the cake pan than needed - you can take a knife and carefully remove the excess dough above the point where the two are connected. (The cake will rise a little during baking, so don't worry if it seems a bit sunken in at this step)
22. Lightly score the top dough with a fork dipped in cold water, taking care not to pierce the top dough layer. This is purely aesthetic, so go nuts - draw whatever you want!
23. Finally, brush the rest of the egg wash onto the top of the cake - use all of it!
24. Bake at 355 F for about 40 to 45 minutes (or until golden brown)
25. When done baking, let cool in the pan for about 5 to 10 minutes, then remove from the pan and let the cake cool for at least 30 minutes before serving. This cake is even better when served cold!