Preheat oven to 180 degrees C. Lightly grease a 23cm round springform pan.
To make the crust: mix the biscuit crumbs and brown sugar together in a bowl. Stir in the melted butter until combined. Press the mixture evenly into the base of the prepared pan.
To make the filling: Beat the cream cheese and sugar with electric mixer until smooth. Beat in the egg yolks, one at a time, scraping the sides of the bowl after each addition. Stir in the lemon zest, lemon juice, vanilla and sour cream until combined.
Beat the egg whites in a small bowl with electric mixer until soft peaks form. Continue beating while gradually adding extra sugar until mixture is thick and glossy. Gently fold meringue, in batches, into the cream cheese mixture.
Pour the filling into the prepared pan and place in a large baking dish. Pour enough hot (not boiling) water into the baking dish to come halfway up the sides of the springform pan. Bake about 50 minutes or until just set in the centre. Turn oven off; cool cheesecake in oven with the door ajar. Refrigerate at least 4 hours, or overnight.
To make the topping: place 1 cup blueberries and sugar in a saucepan and cook over medium heat about 5-7 minutes or until berries begin to break down. While still hot, strain the berries through a sieve over a bowl, reserving the juice. Discard berry pulp. Allow the juice to cool.
Mix remaining 2 cups blueberries and lemon juice together in a large bowl. Stir in the strained blueberry juice. Just before serving, pour the blueberry topping over the cheesecake.