• Preheat the oven to 230°C/210°C fan/450°F. Place a baking tray on the upper shelf - first make sure there is enough space for the tin and the paper.
• Line a 8-9 inch springform baking tin with a square sheet of baking paper. First, grease the tin with some butter then push the paper into the corners, sticking to the buttery edges. Don't worry about it bunching up. Take another square of paper and repeat the process at 90° to the previous piece.
• In a large bowl, beat the cream cheese with a wooden spoon until mailable. Add the sugar and stir to combine.
• Grate in the lemon zest, add the vanilla extract then crack in an egg. Whisk to combine, then add each egg and the extra yolk one at time, whisking with each addition.
• Pour in the cream and the crème fraiche and whisk until everything is well blended. It will be fairly liquid so it may seem doubtful that it will ever set into a cheesecake but have no fear.
• In a small bowl, sift the cornflour. Add a couple of spoonfuls of cheesecake mixture and stir to create a slurry. Pour it into the creamy custard, add the pinch of salt, then stir to make sure it's all well mixed. Pour it all into the lined tin and tap it a few times to make sure there are no air bubbles.
• Carefully place the tin on the baking tray in the oven and leave to bake for 30 minutes. From there, you need to be on guard!
• Rotate the tin to make sure every side is getting the heat. The centre will still look like liquid. If the surface isn't blackened, don't worry, give it another 7-8 minutes or so - in this time, the centre will start to set quite quickly so keep your eye on it - then set the dial to the grill setting. Check every minute, rotating the tin to ensure even burning (a sentence I never thought I'd write). Between 40-45 minutes in the oven is about right, although if you'd like the centre to be more wibbly, reduce the time to around 35 minutes. Either way, when you jiggle the pan, the centre needs to ripple.
• Turn off the oven, open the door and leave the cheesecake inside for 5 minutes as it adjusts to the temperature. Place it on a cooling rack and leave for two hours, then put it in the fridge overnight. The next day, remove it from the tin, peel off the paper and cut large creamy slices.

For the poached rhubarb

• Place the chopped rhubarb in a frying pan, cover with the sugar and water, and add the spices of your choice. Set the heat to medium high to melt the sugar. Stir it all to ensure even cooking.
• Once the water starts to bubble, cook the rhubarb for up to 5 minutes depending on its thickness. For thicker pieces, they may need an extra minute. Remove them from the pan, then continue to boil the syrup for another minute or so until a bit thicker. Pour it into a bowl to cool slightly.
• Serve the poached rhubarb with the cheesecake either warm or cold.