In a food processor, combine the flour, sugar, salt, and cold butter (not too hard), cut into pieces. Pulse until the mixture resembles coarse crumbs. Then add the cold water mixed with the egg yolk.

Mix just until the dough comes together. It should be cohesive and smooth, with no visible flour, but not fully formed into a ball. Turn it out onto a work surface and gently press the dough forward with the palm of your hand 2 to 3 times to bring it together without kneading.

Shape the dough into a ball, flatten it slightly, and wrap it in plastic wrap. Chill in the refrigerator for at least 45 minutes to 1 hour to help prevent shrinking during baking.

After chilling, roll out the dough on a lightly floured surface to about 4 mm (1/6 inch) thick. Line a 9-inch (24 cm) springform pan, greased and lightly floured, and trim the excess with a knife.

Prick the bottom of the crust with a fork and place it in the freezer while you prepare the filling.

Separate the egg whites from the yolks.

Beat the egg whites until stiff peaks form, gradually adding one-third of the sugar.

In a large mixing bowl, whisk the egg yolks with the remaining sugar, vanilla extract (or vanilla sugar), and lemon zest until slightly pale.

Sift in the flour and cornstarch, then gently mix until smooth, without overwhipping.

Add the quark in three additions, mixing gently without whisking, until smooth and well combined.

Fold in the whipped egg whites gradually, working in batches. I like to use a whisk, lifting the mixture from the bottom up to keep it light and airy. Gently tap the whisk against the side of the bowl from time to time. You can also use a spatula if you’re worried about deflating the egg whites.

Remove the pan from the freezer and pour the filling over the crust. Then gently stir with a wooden skewer to release any air bubbles, which helps prevent small holes in the filling after baking.

To prevent the top from cracking, after about 25 minutes of baking, gently run the tip of a knife around the edge of the cheesecake, between the filling and the crust, as shown by the gray arrow in the photo below.

At the end of baking, the cheesecake should be set and no longer jiggly. If you insert a wooden skewer into the center, it should come out clean.

Remove the pan from the oven and let the cheesecake settle until it drops back to the level of the pan. This takes about 10 minutes. Then place a round cooling rack on top and carefully invert it.

Serve the cheesecake dusted with powdered sugar and accompanied by a raspberry sauce.