Preheat the oven to 180 C (160 C fan), and line the bottom of a 20cm springform tin with greaseproof paper. Blitz the biscuits and orange zest in a food processor until the biscuits are finely ground, then tip in the melted butter and process until it’s just mixed. Tip the crumb into the prepared cake tin and press it down with a glass or the back of a spoon so that it’s smooth and compacted. Put the tin into the fridge while you make the filling.
Make the filling: in a large mixing bowl, use an electric hand whisk to beat together the cream cheese, sour cream and sugar. Add the eggs and egg yolks and mix until smooth, then add in the orange and lemon juice.
Wrap two layers of foil securely around the outside of the cake tin - covering the bottom and up the sides, to prevent any water seeping in. Put the tin into a deep oven tray or dish, to act as a water bath, and boil the kettle.
Pour the cheesecake filling into the tin, and cover the top of the tin loosely with foil, then put the whole thing into the oven. Pour boiling water into the water bath, so that it comes half-way up the cheesecake. Bake the cheesecake for 1hr 15 minutes, until just set. It will have firm sides but still wobble in the middle when you move the tray. Remove the cake tin from the water bath, and leave the cheesecake to cool slightly, in its tin, while you make the glaze.
Make the glaze: warm the prosecco and sugar in a small pan. Let it come to a simmer then take it off the heat and allow it to cool for 5 minutes. Sprinkle the powdered gelatine over it and whisk it together until the gelatine has fully dissolved. You may need to return it to the heat for a few moments to help the gelatine dissolve but don’t let it come to a boil. Once it’s all dissolved, stir in the Aperol, then put it into a shallow dish and into the fridge for about 15 minutes, until it’s thickened but is still pourable. Once it’s started to set, give it a quick stir with a fork and pour it on top of the cheesecake, then put the cheesecake in the fridge for at least 4 hours, or overnight.
Serving the cheesecake: run a hot pallet knife around the edge of the cheesecake to loosen it from the edge of the tin. Carefully transfer it to a serving plate then serve.