Melt the butter in a saucepan. Mix in the brown sugar and crushed biscuits. Press into a greased cake tin and chill in the fridge.
Mix the mascarpone and 110g caster sugar together, and set aside. Whip the double cream until thick and likewise set aside.
Melt the white chocolate in the microwave. Stir every 30 seconds to ensure it doesn't burn. When liquid, fold it and the cream into the mascarpone, and allow to cool.
Spread the mixture over the biscuit base, and return to the fridge.
To make a raspberry sauce, take half the raspberries and mash in a saucepan. Add the sugar, orange juice and water, and bring to the boil. Simmer for about 5 minutes, then take off the heat. Blend the sauce and allow to cool until it's thickened.
Use a spoon to make shallow grooves in the top of the cheesecake, and fill the grooves with sauce. Keep behind some sauce to pour over when serving.
Use the remaining raspberries to decorate the cheesecake. Return to the fridge for several hours until ready to serve. Enjoy!