In a large bowl, whip the 500 g quark with 1 packet vanilla sugar and 100 g sugar for about 2-3 minutes until light and well combined. Gently fold in the whipped cream until just blended.
Mix the 1 packet custard powder (cream flavor) with a small amount of the 500 ml milk to form a smooth paste. In a saucepan, heat the remaining milk with 2 tablespoons sugar over medium heat for about 5-7 minutes until hot but not boiling. Stir in the custard paste and stir constantly for 2-3 minutes until thickened. Pour into a bowl and let cool to room temperature for about 30 minutes, or refrigerate for up to 1 hour.
In a glass bowl, layer the quark and cream mixture from step 1, followed by the 500 g applesauce, and then the cooled custard pudding. Top with a dollop of whipped cream and sprinkle with brittle.