• Set aside a few of the best looking raspberries to decorate the dessert.

Make the Raspberry Sauce

• Combine the remaining raspberries, sugar and lemon juice in a pot over medium heat and cook for a few minutes until the raspberries have broken down and are cooked (don't simmer too long, we're not making jam.)
• Set the raspberry sauce aside to cool. Take about a third of the raspberry sauce and put into a fine sieve, pressing the berries to extract as much rasberry syrup as possible. Cover and refrigerate until needed.

Prepare the Tiramisu

• Set up a double boiler (if you don't have one) by placing a glass bowl over a little hot water (the bowl should not touch the water) over low heat.
• Using an electric hand mixer, beat the egg yolks and remaining sugar off the heat for a few minutes, then transfer the bowl over to the barely simmering water in the pot until the temperature reaches 150 degrees F (or 65 C.)
• Continue beating for a minute or two, then allow to cool, stirring occasionally so it doesn't create a skin.
• Add the mascarpone to the mixture, and stir until well-combined.
• Melt the white chocolate and add to the egg and mascarpone cream.
• Pour some cold milk into a bowl. Begin dipping the ladyfinger biscuits into the coffee, once on each side. Do this quickly (no more than one second each side), then place each one on the platter (or in the dish) in a row (this is the original method).
• Begin dipping the ladyfinger biscuits into the milk, once on each side. Do this quickly (no more than one second each side), then cut the cookie as needed for the bottom layer, and place into the glass or containers you'll be using.
• Spread a little of the raspberry sauce over the soaked biscuit, then add a layer of white chocolate mascarpone cream.
• Repeat this, and end with the cream (make all 8 servings in this manner.)
• Cover with plastic wrap and refrigerate for at least 4 hours, but preferably overnight. When ready to serve, remove from the refrigerator, and dust generously with cocoa (from a sieve) or top with the smooth raspberry sauce (which was sieved.)
• Decorate with fresh raspberries and shaved white chocolate, if desired and serve cold.