In a medium saucepan, combine fresh raspberries, sugar, and water over medium heat. Simmer for about 10 minutes until the raspberries break down and the sauce thickens. Dissolve cornstarch in water and stir it into the mixture. Cook for another minute until glossy.

In a mixing bowl, whisk together egg yolks and sugar until light and fluffy. Place over a double boiler, whisking continuously for 5-7 minutes until thickened. Fold in melted white chocolate and let cool.

Whip heavy cream until stiff peaks form, then fold a small portion into the egg yolk mixture to lighten it, and gently fold in the remaining whipped cream.

Line a loaf pan with plastic wrap. Layer crushed biscuits, half of the cream mixture, cooled raspberry filling, remaining cream mixture, and top with another layer of biscuits.

Cover tightly with plastic wrap or aluminum foil and freeze for about 4-5 hours or overnight until firm.

To serve, unmold by lifting with plastic wrap. Let sit at room temperature for a few minutes, slice and enjoy! Decorate with fresh raspberries if desired.