Macerate the berries: In a bowl, combine the strawberries, raspberries, sugar, lemon juice, lemon zest, and a pinch of salt. Toss gently and let sit for 15 minutes, until the berries begin releasing their juices while still holding their shape.

Make the lemon soak: In a shallow bowl, whisk together the milk, sugar, and lemon zest. Let it infuse while you prepare the cream.

Make the mascarpone cream: In a large bowl, combine the mascarpone, heavy cream, sugar, lemon zest, vanilla if using, and a pinch of salt. Beat until smooth and thick enough to hold soft peaks. Be careful not to overwhip.

Prepare the berries for assembly: Using a slotted spoon, remove the berries from their juices so the dessert does not become too loose.

Assemble in coupe glasses: Quickly dip each ladyfinger into the lemon milk, about 1 second per side. Layer ladyfingers, mascarpone cream, and macerated berries into each coupe. Repeat until full, finishing with a smooth layer of mascarpone cream.

Or assemble in a tray: Quickly dip the ladyfingers into the lemon milk and arrange them in a small tray. Spread over a layer of mascarpone cream, spoon over macerated berries, then repeat with another layer of dipped ladyfingers and cream. Finish with mascarpone cream on top.

Chill: Refrigerate for at least 1 hour, preferably overnight.

Finish and serve: Just before serving, dust generously with freeze-dried strawberry powder.