1. Add raspberries, sugar, and lemon juice to a saucepan. Heat until bubbling, then reduce to a simmer. Stir and mash berries occasionally.

2. Simmer for 23–25 minutes until thickened. Cool in a shallow bowl in the fridge until room temperature or colder.

3. For the syrup, heat sugar, water, and raspberries until boiling. Simmer for 3 minutes, then strain and stir in limoncello. Cool completely.

4. In a bowl, whisk mascarpone, powdered sugar, lemon juice, and vanilla until smooth. Add heavy cream and whip to medium-stiff peaks.

5. Spread a thin layer of mascarpone cream in a dish. Dip ladyfingers in syrup and layer them in the dish.

6. Spread half the mascarpone cream evenly, then half the raspberry jam.

7. Repeat layers (ladyfingers and mascarpone). Cover and refrigerate for at least 8 hours or overnight.

8. Before serving, spread remaining raspberry jam on top and decorate with fresh raspberries and lemon slices.