To make the base, put the crackers in the bowl of an electric mixer fitted with the paddle attachment or a food processor fitted with the plastic blade. Process gently to obtain a powder. Add the butter, sugar and flour. Keep mixing gently until the mixture has a creamy dough consistency.Using a rolling pin, roll the base between two sheets of baking paper to 1 cm thickness. Refrigerate for 1 hour. Cut out a 12 cm × 24 cm rectangle (for the base) and two long 24 cm × 3 cm strips (for the long sides).Place a 12 cm × 24 cm × 7 cm rectangular dessert frame on a baking tray lined with baking paper. Put the cracker base in the bottom of the frame and the two strips along the long sides. Set aside.For the cheesecake mixture, preheat the oven to 120°C. In a stainless-steel bowl, whisk the fromage blanc, cream, icing sugar and cornflour. Whisk in the egg then the vanilla seeds and lemon juice, until the mixture is smooth.Pour the mixture into the lined frame and bake for 20–40 minutes, making sure you open the oven door for a few seconds every 10 minutes to let the steam out and avoid cracks. When you tap the frame, the cream should be set and wobble only slightly. Allow to cool to room temperature, then refrigerate, ideally overnight.To make the vanilla panna cotta, hydrate the gelatine (page Note) in very cold water. Bring 100 g of the cream, the sugar and the vanilla bean seeds to the boil, then remove from the heat. Whisk in the drained gelatine.Add the rest of the cream, pour over the cheesecake and refrigerate for 2 hours to set. Using a kitchen blowtorch, gently heat the sides to remove the frame, then cut into individual portions.Note• Leaf gelatine has been dehydrated and must be rehydrated in order to melt it into a mixture. If it isn’t hydrated well, it will absorb any missing water from the mixture itself, causing it to shrink. Immerse the gelatine in a bowl of very cold water (it melts at low temperatures). Let it soak for at least 15 minutes, then drain it and squeeze it between your hands before adding it to the mixture. Gelatine ‘glues’ mixtures together; in other words, it gives them their structure. The setting time is quite quick. Use the mixture straight away, so that the gelling power kicks in as soon as the mixture is put in place, or set it aside and whisk it before using to restore its consistency.Recipes and images from Patisserie by Mélanie Dupuis and Anne Cazor (, $59.95 hbk).View our Readable feasts review and more recipes from the book .