Parisian Flan.

“Sir Bones: is stuffed, / de world, wif feeding girls.” | Orangette
From Dorie Greenspan’s Paris Sweets

This recipe, adapted by Greenspan from the esteemed pâtissier Pierre Hermé, makes a traditional Parisian flan, which (unlike the flan generally familiar to Americans, jiggly or gelatinous or covered in caramel) is a custardy almost-cake in a flaky pastry crust.
It is unbearably delicious.
Dorie Greenspan, I apologize for my lack of faith.

For the crust:
1 stick plus 5 Tbs (6 ½ ounces) unsalted butter, at room temperature
½ tsp salt
½ tsp sugar
½ large egg yolk (lightly beat one yolk, and then spoon out half)
3 ½ Tbs whole milk
2 cups all-purpose flour

For the filling:
1 ½ cups whole milk
1 2/3 cups water
4 large eggs, at room temperature
1 cup sugar
½ cup cornstarch, sifted

To make crust:
Put all of the crust ingredients except the flour in the bowl of a food processor and process until the mixture is soft and creamy.
Add the flour and pulse in quick spurts until the dough forms a ball—then stop.
Turn the dough out onto a smooth work surface, gather it together in a ball, and flatten into a disk.
Wrap the disk well in plastic wrap.
Chill the dough for at least four hours. [Dough can be kept in the fridge for up to three days.]

Line a baking sheet with parchment or wax paper and keep close at hand. Working on a generously floured work surface, roll the dough out to a thickness of between 1/8 and ¼ inch. Cut out a 12-inch circle of dough and transfer it to the lined baking sheet. Cover and chill dough for at least thirty minutes.

Butter a 9-inch/22cm springform pan and put it on a parchment-lined baking sheet.
Fit the dough into the pan, pressing it evenly along the bottom and up the sides.
Don’t worry if the dough tears, as it did for me—just patch it back together and carry on!
Trim the dough so that it comes 1 ¼ inches/3cm up the sides of the pan.
Chill the dough for at least two hours and up to overnight.

Center a rack in the oven, and preheat the oven to 350 degrees Fahrenheit/180C.

Line the crust with parchment paper and fill it with beans, rice, or pie weights.
Bake the crust for 18 to 20 minutes, until it is set but not browned. Pull it from the oven, remove the paper and beans, and cool to room temperature.

To make filling:
Bring the milk and water to a boil in a medium saucepan.
Meanwhile, in another medium saucepan, preferably one with a heavy bottom, whisk the eggs, sugar, and cornstarch together.

Whisking without stop, drizzle ¼ of the hot liquid over the egg mixture.
When the eggs are warmed, add the rest of the liquid in a steady stream.
Put the saucepan over medium heat and, whisking constantly and energetically, heat the filling just until it thickens and a couple of bubbles pop to the surface.
Immediately remove from the heat, and push the filling through a sieve into a bowl. Let the filling cool for about 30 minutes.

Center a rack in the oven, and preheat the oven to 375 degrees Fahrenheit/190C.

Put the pan with the crust on a parchment-lined baking sheet (if it isn’t still on one), and scrape the filling into the crust.
Smooth the top.
Slide the baking sheet into the oven and bake the flan for one hour, or until the filling is puffed and golden and just jiggles in the center when you tap the pan.
Transfer the baking sheet to a cooling rack, and let the flan cool to room temperature; then chill the flan for at least six hours, preferably overnight.

According to Mr. Hermé, the flan should be served cold.