Preheat your oven to 325°F (160°C). Grease a 9-inch (23 cm) springform pan and line the bottom with parchment paper if you'd like to make removing the cheesecake a little easier later on.

In a medium bowl, combine the graham cracker crumbs, melted butter, and salt. Mix until all the crumbs are evenly moistened, then press the mixture firmly into the bottom of your prepared pan (and slightly up the sides if you prefer). Bake for 8–10 minutes, then set aside to cool slightly while you prepare the filling.

In a large mixing bowl, quickly whisk together the quark, eggs and sugar so it forms a cohesive batter (doesn’t have to be smooth!). Then add the heavy cream, cornstarch, vanilla, and salt. Mix everything just until you get a creamy filling. There's no need to beat it for too long, and it probably won’t be smooth - quark (and many of its substitutes) are a bit grainy so that will reflect on the batter.

Pour the filling over your prepared graham cracker crust and gently smooth the top with a spatula. Give the pan a light tap on the counter to release any large air bubbles.

Bake for 55–65 minutes at 325°F (160°C), until the edges look set but the center still has a slight wobble when you gently shake the pan. Don't wait for the entire cheesecake to become firm, as it will continue setting while it cools. When it’s done, turn off the oven, crack the door open slightly, and leave the cheesecake inside for another 20 minutes. This allows it to cool down more gradually and helps prevent large cracks on the surface.

Remove the cheesecake from the oven and let it cool completely at room temperature. Once cooled, transfer it to the refrigerator for at least 3–4 hours, although I recommend leaving it overnight if you have the time. The texture will be even better!

Carefully remove the cheesecake from the springform pan and slice it with a sharp knife, wiping the blade between cuts for cleaner slices. Serve it as is, or finish with a light dusting of powdered sugar, some berries etc.