1. In a large bowl, whisk together the mascarpone cheese and sugar until light and creamy.
2. Stir in the melted white chocolate and vanilla extract, mixing until well combined.
3. In a separate bowl, whip the heavy cream until soft peaks form.
4. Gently fold the whipped cream into the mascarpone mixture, being careful not to deflate the mixture.
5. In a shallow dish, combine the coffee and raspberry liqueur.
6. Dip each ladyfinger into the coffee mixture, allowing them to soak briefly, then layer them in a 9×13 inch dish.
7. Spread half of the mascarpone mixture over the ladyfingers, smoothing it into an even layer.
8. Scatter half of the raspberries over the mascarpone layer.
9. Repeat the layers with the remaining ladyfingers, mascarpone mixture, and raspberries.
10. Dust the top with cocoa powder for a classic finish.
11. Refrigerate the tiramisu for at least 4 hours, or overnight, to allow the flavors to meld.

Remember, patience is key! Allowing the tiramisu to rest overnight will enhance the flavors and texture, making it a truly unforgettable experience.