Mix together mascarpone, lemon curd, vanilla extract and icing sugar until smooth. Pile into pastry case and top with berries. Chill for 1hr.
Meanwhile, make lemon syrup. Place caster sugar and 2tbsp water in small saucepan over low heat. Allow sugar to dissolve, then increase heat and boil for 3mins. Remove from heat, add lemon zest and leave to cool completely.