For the base:
1) Preheat the oven to 170C/Gas Mark 3.
2) In a mixing bowl, combine the ingredients with a fork until evenly moistened. Lightly coat the bottom and sides of a 20-cm springform tin with non-stick cooking spray.
3) Pour the crumbs into the tin and, using the smooth bottom of a glass, press the crumbs down into the base and 2.5cms up the sides. Refrigerate for 5 minutes.
For the filling:
1) In the bowl of an electric mixer, beat the cream cheese on low speed for 1 minute until smooth and free of any lumps. Add the eggs, 1 at a time, and continue to beat slowly until combined. Gradually add sugar and beat until creamy, for 1 to 2 minutes.
2) Add sour cream, lemon zest, and vanilla. Periodically scrape down the sides of the bowl and the beaters. The batter should be well-mixed but not over-beaten. Pour the filling into the base-lined tin and smooth the top with a spatula.
3) Set the cheesecake tin on a large piece of aluminium foil and fold up the sides around it. Place the tin in a large roasting tin. Pour boiling water into the roasting tin until the water is about halfway up the sides of the cheesecake tin; the foil will keep the water from seeping into the cheesecake.
4) Bake for 45 minutes. The cheesecake should still jiggle (it will firm up after chilling), so be careful not to overcook. Let cool in tin for 30 minutes. Chill in the refrigerator, loosely covered, for at least 4 hours.
5)Loosen the cheesecake from the sides of the tin by running a thin metal spatula around the inside rim. Unmould and transfer to a cake plate. Using a spatula spread a layer of warm lemon blueberry topping over the surface.
6) Slice the cheesecake with a thin, non-serrated knife that has been dipped in hot water. Wipe dry after each cut.
for the warm lemon blueberries:
1) In a small saucepan, add all the ingredients and simmer over medium heat for 5 minutes or so until the fruit begins to break down slightly.
2) Leave to cool before spreading on cheesecake.