Baked Blueberry Cheesecake

For the biscuit base:
40g / 1 1/2 oz butter, plus more for greasing
75g / 3 oz digestive biscuits
25g / 1 oz pecan nuts
25g / 1 oz plain chocolate, broken into pieces

For the filling:
250g / 9 oz curd cheese
250g / 9 oz cream cheese
grated zest of 1 lemon and juice of 1/2 lemon
2 eggs
100g / 3 1/2 oz caster sugar
seeds of 1 vanilla pod
350g / 12 oz blueberries
1 tbsp plain flour

Make the base: butter a loose-bottomed 23cm / 9 in round cake pan. Place the digestive biscuits and the pecan nuts in a food processor and process until fine or chop the nuts and crush the biscuits with a rolling pin. Melt the butter and chocolate in a small bowl set over a pan of hot ,not boiling, water. Stir this into the biscuit mixture, then spread over the bottom of the cake pan and chill.

Preheat the oven to 180ºC / fan oven 160ºC / gas mark 4. Make the filling: sieve the curd and cream cheeses into a bowl and add the lemon zest and juice, the eggs, caster sugar and the vanilla seeds. Beat to a smooth batter.

Toss the blueberries in the flour, then fold them into the batter. Pour over the base and bake for 35 minutes, or until just set. Turn off the oven, leave the door ajar and allow the cheesecake to cool in the oven. Chill for a few hours or, preferably, overnight.