Sort the raspberries (if using frozen, let them thaw completely). Divide between 4 glasses.
Squeeze the lemon. In a bowl, mix the quark, mascarpone, sugar, bourbon vanilla sugar, and lemon juice. Add about 5 tablespoons of milk, stirring until the mixture reaches a spreadable consistency that is not too runny.
Spoon the cream mixture over the raspberries in each glass.
Using a grater or vegetable peeler, grate or shave the white chocolate. Sprinkle the chocolate over the cream in each glass.