Photo: Helen Cathcart
Put a large pot with a lid over a medium-high heat and add the oil and salt. Drop in a couple of popcorn kernels and cover the pan with a lid. When the kernels start to pop, add the rest of the corn and cover with the lid. Shake the pan to evenly coat the kernels, and leave to heat up, shaking the pan around gently when it starts popping to make sure the unpopped kernels get to the heat and the popped ones don’t burn on the bottom of the pan. Set the lid slightly ajar to release some of the steam and make crisper popcorn. Once the popcorn has stopped popping every few seconds, take it off the heat and leave it to one side until all the popping has stopped completely.
Grease the cake tin and line the base and sides with greaseproof paper.
Put the biscuits in a sealed food bag and smash them into crumbs with a rolling pin, or put them in a food processor and grind to coarse crumbs. Transfer to a mixing bowl and stir in a small handful of popcorn and a pinch of sea salt.
Melt the butter in a saucepan over a low heat and pour it over the crumbs. Mix it all together with a fork and put your mixture into the cake tin. Tap the side of the tin with the flat of your hand to even it out and gently compress the mixture with the back of a large spoon until it’s packed in and level. You want it fairly well packed so that it holds together. Transfer to the fridge to cool.
Melt the butter, milk, cream, sugar and salt together in a medium non-stick saucepan, and, stirring continuously, bring to the boil. Although it may look super tempting, don’t swipe your finger over the spoon: flesh and boiling sugar don’t mix. Turn down to a simmer and cook for 10 minutes, stirring occasionally. Remove from the heat and set to one side. If, when it’s cooler, the mixture is stiff, warm it up over the heat with a splash of milk to loosen it. You want it still warm and runny so that you can pour it over the cheesecake.
Put the mascarpone or soft cheese, quark and icing sugar into a mixing bowl or the bowl of a stand mixer, and beat together. If you don’t have a stand mixer use an electric hand whisk. Mix until well combined and thickening, then add the cream and continue to mix. You want it thick, but not over-whipped. Pour in about half the salted butterscotch sauce, and fold it through the cream cheese mixture to create a ripple effect. Taste it and add more butterscotch sauce or salt if you feel it needs it.
Pile the mixture on top of the buttery biscuit base and smooth it down with the back of the spoon or a palette knife. Cover with clingfilm (plastic wrap) and chill for at least 2 hours, then scatter the rest of the popcorn over the top, drizzle with the remaining butterscotch sauce, and serve.
This recipe is taken from A Lot on Her Plate by Rosie Birkett (Hardie Grant, £25)