Make the cheesecake base: preheat the oven to 180 C (160 C fan), and line the bottom of a 20cm springform tin with greaseproof paper. Blitz the biscuits 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: pre-heat the oven to 180 C (160 C fan). In a large mixing bowl, whisk together the cream cheese, sour cream and sugar. Beat in the eggs and egg yolks, one at a time, then the lemon juice.
Wrap two layers of foil securely around the outside of the cake tin - 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 1 hour or 1 hour and 15 minutes, until just set. Remove the cake tin from the water bath, and leave the cheesecake to cool, in its tin, for four hours or overnight.
Make the cake: preheat the oven to 180 C (160 C fan). Grease a 20cm springform cake tin. Melt the butter and sugar in a small saucepan, until the sugar has dissolved, then pour it into the cake tin. Arrange a layer of pineapple rings and cherries, in a pretty pattern, then put the tin to one side.
Make the cake mixture by beating together the butter and sugar in a large mixing bowl. Add in the eggs, one at a time, followed by the flour, baking powder, vanilla and salt. Mix it all together then add a few tablespoons of milk, if needed to loosen up the batter. Pour this over the pineapple layer, then bake the cake for 25-30 minutes, until a skewer comes out clean.
Assembling the cheesecake: while the cake is baking, take the cheesecake out of the fridge and run a palette knife around the edge to loosen it up. Then remove the tin and carefully put the cheesecake onto a serving plate.
Let the cake cool for just one minute once you remove it from the oven. Remove the springform edge but leave the upside-down cake on the base of the tin. Use a tea towel to carefully turn the cake on top of the cheesecake, then gently remove the base of the tin, leaving the upside down cake on top. Warm up the caramel sauce and drizzle on top of the cheesecake, then serve, with extra cherries on the side.