In a small saucepan, combine fresh or frozen raspberries with sugar over medium heat. Stir occasionally for about 10 minutes until the mixture thickens. Once thickened, remove from heat and let cool completely.

In a large mixing bowl, beat mascarpone cheese with heavy cream and powdered sugar using an electric mixer for about 3-5 minutes until smooth and creamy.

Dip each ladyfinger in the cooled raspberry syrup and arrange a single layer in an 8-inch square dish. Spread half of the mascarpone filling over the ladyfingers.

Grate half of the ounce of white chocolate over the mascarpone filling. Repeat the layer with dipped ladyfingers and top with remaining mascarpone filling.

Finish by grating the rest of the white chocolate on top. Cover with plastic wrap and refrigerate for at least 6 hours.