Pumpkin Cheesecake

2. For the sponge base, preheat the oven to 200C/400F/gas mark 6. Whisk the egg whites in a bowl until softly stiff. Gradually fold in the caster sugar, then the egg yolks. Sift the cornflour and flour together over the mixture and then fold in carefully.

3. Line a baking sheet with baking parchment. Spread the sponge mixture out to an area approximately 30cm square – it needs to be an even thickness, but not necessarily a neat square. Bake for 7–10 minutes until golden brown and springy when pressed. Invert on to a wire rack to cool and then peel off the paper. Lower the oven setting to 170C/325F/gas mark 3.

4. For the cheesecake you will need a 23–24cm springform cake tin about 6cm deep. Cut out a round from the sponge base to fit exactly inside the tin, using the base of the tin as a guide. It is preferable to cut the sponge a little larger and trim it to fit, rather than cut it smaller and leave gaps that the pumpkin filling might leak through.

5. For the filling, beat the mascarpone, crème fraîche, soured cream, 50g of the remaining sugar, the vanilla seeds (or extract) and 2 egg yolks together in a bowl until evenly blended. Stir in the pumpkin purée.

6. Whisk the 2 egg whites in another bowl until softly stiff. Gradually whisk in the remaining 25g sugar and gently fold into the pumpkin mixture. Pour the filling over the sponge base in the tin and bake for 40–50 minutes until lightly firm on top.

7. Leave the cheesecake to cool and then chill in the tin. Run a table knife around the inside of the tin and carefully unmould on to a flat plate. Serve in wedges, dusted lightly with icing sugar.