Blackberry tart (Torta di more)

INGREDIENTS

• 125 g butter
• 100 g icing sugar
• 1 small pinch salt
• 255 g plain flour
• 1 vanilla pod, scored lengthways and seeds removed, optional
• zest of optional ½ lemon
• 2 large free-range egg yolks
• 2 tablespoons cold milk or water
• 1 vanilla pod
• 500 g mascarpone
• 100 ml single cream
• 3 tablespoons sugar
• 3 tablespoons grappa or vin santo
• 310 g blackberries or other fruit
• 2 tablespoons blackberry or raspberry jam
• 1 small handful fresh baby mint leaves