In a small bowl mix the jam and 2-4 tablespoons of lemon juice together until it is the consistency of thinned sauce.
In another bowl blend 2 tablespoons of raspberry juice with the mascarpone cheese.
Beat heavy whipping cream, sugar, and vanilla together in a mixer until soft peaks are formed.
Add a tablespoon of lemon zest and mascarpone mixture to the whipping cream and gently fold together.
In your dish layer: ladyfingers, raspberry jam sauce, cream mixture, and top with raspberries.
Continue layering until your dish is filled.
Garnish with more lemon zest.