In a medium saucepan, combine raspberries with water. Simmer over medium heat for about 10 minutes, stirring occasionally, until the raspberries break down.

Strain the mixture through a fine mesh sieve into a bowl, pressing to extract as much liquid as possible.

Return the strained liquid to the saucepan, then stir in sugar and lemon juice. Simmer for an additional 5 minutes until the syrup thickens slightly, then chill in the refrigerator.

In a large mixing bowl, whip heavy cream until stiff peaks form.

In another bowl, beat mascarpone cheese with sugar until smooth. Gradually add chilled raspberry syrup into the mascarpone, blending well.

Gently fold whipped cream into the mascarpone mixture until fully incorporated.

Take the chilled raspberry syrup and dip each ladyfinger quickly into it. In an 8-inch dish, arrange the dipped ladyfingers in a single layer at the bottom.

Spread half of the mascarpone filling over the ladyfingers and grate half of the white chocolate over it.

Repeat the dipping with the remaining ladyfingers and place them over the first mascarpone layer.

Spoon the remaining mascarpone filling over the top and decorate with remaining mascarpone and white chocolate.

Cover with plastic wrap and refrigerate for at least 6 hours or overnight.

Before serving, slice into portions and enjoy.