Photo: Jonathan Gregson
Preheat the oven to 180°C, fan 160°C, gas 4. Put the sultanas in a small bowl, add the sherry and 1 tablespoon of hot water from the kettle and leave to soak for 10 minutes.
Line the base and sides of a 25cm round springform cake tin with nonstick baking paper. Tip the ricotta into a large bowl, sift in the icing sugar and beat well to combine. Add the eggs, one by one, stirring well after each addition.
Drain the sultanas and add them to the mixture with the citrus zests, candied peel and the nuts. Stir once again to distribute the ingredients evenly. Spoon the mixture into the prepared tin.
Bake on the middle shelf of the preheated oven for 1 hour, until it feels lightly firm on top when gently pressed in the middle. Leave the cheesecake to cool in the tin, then chill before serving. Carefully release the cheesecake from the tin and transfer to a large plate. Finish with extra candied or glacé fruit, if you like.