Preheat your oven to 180°C (350°F). Prepare a springform pan by greasing it lightly or lining it with parchment paper.

In a bowl, combine the crushed digestive biscuits or graham crackers with the melted butter. Mix well until all crumbs are coated. Press this mixture evenly into the bottom of your prepared springform pan to create a solid crust.

In a large mixing bowl, combine the quark or ricotta cheese, cream cheese, sugar, eggs, vanilla extract, lemon juice, and flour. Use an electric mixer on medium speed until the mixture becomes smooth and free of lumps.

Pour the cheesecake filling over the prepared crust in the springform pan. Smooth the top with a spatula to ensure an even surface.

Bake in the preheated oven for approximately 40-50 minutes, or until the center is set but still has a slight jiggle.

Once baked, turn off the oven and crack the door open. Allow the cheesecake to cool in the oven for about an hour to help prevent cracking.

After cooling, remove the cheesecake from the oven and let it cool completely at room temperature. Refrigerate for at least 4 hours or overnight for the best flavor and texture.

Slice, serve, and enjoy your Classic German Cheesecake, perhaps with a dusting of powdered sugar or fresh fruit on the side.