Melt the white chocolate - I use a double boiler but you can use a heatproof bowl over simmering saucepan of water. I don't recommend the microwave for white chocolate as the high sugar content makes it go grainy very easily. When melted, take off the heat to cool slightly.
When the chocolate had cooled for a couple of minutes, stir in the quark. Beat until smooth and allow to cool completely.
Spread the white chocolate and quark mix onto the pastry case going evenly to the edges. Before it sets, dot with raspberries. Ta-dah!