Preheat the oven to 180 degrees Celsius/ 360 degrees Fahrenheit. Line the bottom of a springform (26 cm/ 10 inches diameter) with baking paper.
Separate the eggs. Beat the egg whites and the warm water until stiffer. Slowly start adding the sugar and continue beating until the egg whites are stiff and glossy. Carefully fold in the lightly beaten egg yolks.
Mix the flour, cornstarch and baking powder and sift them over the egg mixture. Fold in carefully.
Bake: Pour the batter into the prepared springform and bake for about 25 minutes or until a toothpick inserted in the middle of the cake comes out clean.
Cool: Release the cake from the form and let it cool completely on a wire rack.
Bloom the gelatin in cold water according to the packet's instructions, about 10 minutes.
Mix the quark, sugar, vanilla extract and the passion fruit juice in a bowl. Lightly squeeze the gelatin and place it to a saucepan large enough to hold the quark mixture as well later on.
Turn the heat on and gently dissolve the gelatin. This will happen very quickly, stand by and stir. Do not let the gelatin come to a boil.
Mix filling: Remove the saucepan with the gelatin from the heat and slowly start adding the quark mixture, one tablespoon at a time, while stirring continuously.
Refrigerate: Place the mixture in the fridge and leave it until it just begins to set. Don't let it set too much.
Beat the heavy cream until stiff, in the meantime. Gently fold the cream into the quark mixture.
Assemble cake: Slice the cake once. Place one slice on a serving platter and place a cake ring around it. Pour in the filling and cover with the second cake slice.
Mix glaze: To make the glaze follow the packet's instructions. In my case, I mix the two packets of Dr. Oetker Glaze with 2 tablespoons of sugar in a saucepan. Slowly add the juice and the water while stirring to avoid the formation of clumps.
Simmer: Turn the heat on and slowly heat the mixture while stirring continuously, it will take 3-4 minutes until the mixture comes to a boil. Let bubble once or twice, remove from the heat, let stand for 1 minute.
Pour the glaze on top of the cake carefully.
Refrigerate: Place the cake in the fridge for at least 5-6 hours or overnight (best).
Serve: Once the cake is completely set, run a knife inside the cake ring to help release the cake from the ring. Remove the ring and slice the cheesecake.