This oh-so-pretty pudding is wrapped in ladyfingers and contains layers of jelly and set custard decorated with fresh fruit.
For this recipe you will need a deep, 20cm/8in springform cake tin, 2 baking sheets, an electric whisk and a piping bag fitted with a 12mm/⅝in plain nozzle.
Preheat the oven to 190C/170C Fan/Gas 5. Line the base and sides of a deep, 20cm/8in springform cake tin with baking parchment. Line 2 baking sheets with baking parchment and draw ten 11cm/4¼in lines, 2½cm/1in apart on each sheet. Turn the parchment over so the ink/pencil line is underneath, to use as a template.
For the savoiardi, whisk the egg yolks and half of the sugar together with an electric hand whisk until pale, creamy and thick enough to leave a trail on the surface when the whisk is removed (known as the ribbon stage). Add the vanilla extract and whisk again. Sieve the flour, cornflour and salt over the mixture and gently fold in.
In a clean bowl, whisk the egg whites and cream of tartar until soft peaks form when the whisk is removed. Add the remaining sugar one spoonful at a time, whisking continuously to a glossy meringue. Gently fold the meringue into the egg and flour mixture in 3 batches - keeping as much air in the mixture as possible - until all the flour is incorporated.
Spoon the mixture into a piping bag fitted with a 12mm/⅝in plain nozzle and pipe the mixture in straight lines along the lines on the prepared baking parchment. Sieve the icing sugar over the top and bake for 10-12 minutes until fairly firm but a bit spongy (they will harden up as they cool).
Remove from the oven and immediately transfer the sheets of savoiardi onto cooling racks. Leave to cool for 2-3 minutes, then remove form the baking parchment with a palette knife. Leave to cool completely on a wire rack.
For the bavarois, pour the milk into a pan and heat until just under boiling point. Whisk the egg yolks and caster sugar together until pale and creamy. Pour the hot milk over the eggs and whisk together. Drain the gelatine, squeezing out any excess moisture and then add to the mixture. Return the custard to the pan and cook gently until the mixture is thick enough to coat the back of a spoon (do not boil as the custard might split). Remove from the heat.
Transfer to a clean bowl and leave to cool slightly before folding in the passion fruit purée. Leave to cool completely.
In a bowl, whip the cream until soft peaks form when the whisk is removed then fold into the passion fruit bavarois.
When the savoiardi are cold, stand them vertically, next to each other, around the inside edge of the tin. Arrange them tightly together to form a seal and squash them slightly together so they remain upright. Spoon the bavarois into the savoiardi lined tin. Cover with cling film and chill in the fridge for 3-4 hours until set.
For the lime jelly, place the lime zest and juice, sugar and 150ml/5fl oz water in a pan. Bring to the boil, stirring until the sugar has dissolved. Remove from the heat.
Drain the gelatine, squeezing out any excess moisture and add it to the pan. Stir until the gelatine has dissolved, then pass through a fine sieve into a jug. Add the food colouring paste to make a lime green jelly. Leave to cool until just beginning to set, then pour over the surface of the set bavarois and chill for 3-4 hours until set.
When ready to serve, remove the Charlotte from the tin and place on a serving plate or cake stand. Remove the baking paper and decorate with fruit.
