In a mixing bowl, whisk together the mascarpone cheese, heavy cream, powdered sugar, vanilla extract, and lemon zest until smooth and creamy.

Set aside in the refrigerator to chill while you prepare the raspberry layer.

In a small saucepan, combine the fresh raspberries, sugar, and lemon juice over medium heat.

Cook for about 5 minutes, stirring gently until the raspberries break down and the mixture thickens slightly.

Remove from heat and let cool.

Dip each ladyfinger into the lemon juice briefly, then layer them in the bottom of a 9x9 inch baking dish.

Spread half of the mascarpone cream mixture over the ladyfingers.

Spoon half of the raspberry mixture over the cream layer.

Repeat the layers with the remaining ladyfingers, cream, and raspberries.

Cover and refrigerate for at least 4 hours or overnight for best results.

Before serving, garnish with additional raspberries and lemon zest.

Slice and enjoy your refreshing raspberry lemon tiramisu!