1. Preheat oven to 170°C/350°F/Gas 4. Grease and base line 2 x 20cms/8" sandwich tins.
2. Put butter and sugar into a mixing bowl and beat until soft and light. Gradually beat in the eggs, adding a little of the flour.
3. Sieve the remaining flour with the baking powder and fold into the creamed mixture and stir in the water and vanilla extract.
4. Divide the mixture evenly between the two baking tins and bake for aprox 30 minutes until golden brown and the cake springs back when pressed. Turn onto a wire tray to cool.
5. Meanwhile to make the filling, melt the white chocolate, break into pieces and place in a heatproof bowl. Add a little boiling water to a saucepan, placing the bowl on top making sure the base of the bowl doesn’t touch the hot water. Gently stir until chocolate is completely melted.
6. Allow the chocolate to cool a little, stir one third of the cream into the chocolate. Once this is completely mixed through stir in the remaining cream. The chocolate hardens quite quickly so if necessary place back over saucepan with hot water to thin.
7. Spread the bottom layer with some of the ganache and the other layer with jam. Then sandwich the cake together.

To decorate the top of the cake, cover with the remaining ganache, fresh raspberries and white chocolate curls.