Special equipment: 24 cm (9 1/2-inch) diameter spring-form/loose-bottomed tin
Preheat the oven to 350 degrees F. Grease the sides and base of a 9 1/2-inch spring form pan.
Place the biscuits in a food processor, and whiz or pulse until fine crumbs form. Alternatively, place them in a plastic bag and bash with a rolling pin. In a medium bowl, mix the crushed biscuits with the melted butter until combined, and press the mixture down into the base of the pan so that it is nice and even. Spread the blueberries over the base and chill in the refrigerator while you make the topping.
Beat the cream cheese, sugar, vanilla extract and the eggs together in a large bowl, until smooth and creamy. Pour over the top of the blueberries, and then bake in the oven for 40 minutes, or until it is pale golden, and should only wobble very slightly when you gently shake the pan.
Cool the cake in the pan for about 10 minutes, then run a knife around the edge to loosen it, and carefully remove the cheesecake from the pan. Transfer the cake to a serving plate. Sprinkle over a few blueberries, if you wish, then dust with icing sugar. Cut the cake into 12 slices to serve. This cheesecake is best eaten when it is at room temperature.
You can experiment with all kinds of (dry) sweet biscuits or cookies for the base, just crush them the way you would the digestives above. Try using a chocolate biscuit base, and omitting the blueberries.