In a saucepan over medium heat, combine raspberries and water. Simmer for about 10 minutes until the raspberries are soft. Strain the mixture and stir in sugar and lemon juice. Chill the syrup.

In a large mixing bowl, whip heavy cream until stiff peaks form (3-5 minutes) and set aside.

In the same bowl, beat mascarpone cheese, sugar, and raspberry syrup until smooth. Fold in whipped cream.

Dip each ladyfinger into the raspberry syrup briefly and layer in a 9x9 dish. Spread half of the mascarpone filling over it and sprinkle with half of the grated white chocolate.

Repeat the layering with remaining ladyfingers, mascarpone filling, and white chocolate. Cover and refrigerate for at least 6 hours or overnight.