Line a 20cm square cake pan with baking paper, allowing some overhang.
Place sugar, mascarpone and coconut in a large bowl and stir to combine. Transfer half the mixture to a separate bowl.
Using a fork, crush 50g raspberries, then add to one half mixture and stir to combine. Add vanilla to the second bowl and stir to combine.
Spread the white vanilla mixture into the prepared pan and smooth the surface. Spread the raspberry mixture on top and smooth the surface. Cover and chill overnight.
Cut into squares. Serve scattered with the remaining raspberries and dust with icing sugar.