Line a 22cm (base) springform pan with baking paper. Process biscuits until mixture resembles fine breadcrumbs. Add the butter. Process until combined. Press mixture over base of prepared springform pan. Place in the fridge.
Meanwhile make filling: warm lemon curd and blueberries in a pan over low heat for 5 minutes, until berries are soft and releasing their juice. Set aside to cool.
Whisk eggwhites in a large bowl with an electric mixer until soft peaks form. Gradually add icing sugar and beat until mixture is a thick and glossy meringue.
In a separate large bowl, lightly whisk the mascarpone until smooth. Fold in the double cream, then the meringue. Add the cooled berries. Swirl until mixture is just combined. Pour the blueberry filling over the biscuit base in the pan and smooth top. Cover with plastic and freeze for 4 hours or overnight.
Serve frozen cheesecake with the extra fresh blueberries.