Instructions
Position an oven shelf in the middle of the oven and preheat to fan 160°C (conventional 180°C/gas mark 4). Begin by lining the base of a 23cm springform cake tin with parchment paper to ensure your cheesecake lifts out effortlessly later. To create the crust, melt the butter gently in a medium pan, then stir in the biscuit crumbs and sugar until the mixture is uniformly moistened. Press this crumbly mixture firmly into the base of the prepared pan, creating an even layer. Bake the crust for 10 minutes until it's golden and fragrant, then transfer to a wire rack to cool while you prepare the filling. Increase the oven temperature to fan 200°C (conventional 240°C/gas mark 9). Using a tabletop mixer fitted with the paddle attachment, beat the cream cheese on medium-low speed until it becomes smooth and creamy, about 2 minutes. Gradually add the sugar, then the flour and a pinch of salt, making sure to scrape down the sides of the bowl and paddle twice to ensure the mixture is fully combined. Switch to the whisk attachment and add the vanilla extract along with fresh lemon zest and lemon juice, blending these refreshing flavors into the batter. Incorporate the eggs and additional yolk one at a time, whisking thoroughly after each addition and scraping down the bowl and whisk at least twice to maintain a smooth consistency. Stir the 284ml carton of sour cream until smooth and measure out 200ml to add to the bowl on low speed. Carefully blend it in without over-beating; the batter should end up smooth, light, and airy. Brush the sides of the springform tin with melted butter to prevent sticking and place the tin on a baking sheet. Pour in the filling, smoothing the surface meticulously with a knife to eliminate any lumps and achieve a perfectly even top. Bake the mixture for 10 minutes at the higher temperature, then reduce the oven to fan 90°C (conventional 110°C/gas mark ¼) and bake for an additional 25 minutes. A gentle shake of the tin should reveal a slight wobble in the center, indicating the filling is just set. For a creamier center, turn off the oven and crack the door open, letting the cheesecake cool inside for 2 hours. If you prefer a firmer texture, leave the oven door closed as it cools. Expect a slight crack to form on top as it settles, which is perfectly normal. Prepare the topping by combining the reserved sour cream with the 142ml carton sour cream, caster sugar, and lemon juice. Spread this luscious mixture evenly over the cooled cheesecake, right to the edges. Cover the cheesecake loosely with foil and refrigerate for at least 8 hours or overnight to allow the flavors to meld and the texture to set fully. Before serving, run a round-bladed knife carefully around the sides of the tin to loosen the dessert. Unlock the springform and gently slide the cheesecake off the bottom onto a serving plate, then peel away the parchment paper from underneath. Tip: For clean slices, chill the cheesecake thoroughly and warm your knife blade under hot water between cuts. This will help your knife glide smoothly through each slice, showcasing that perfect creamy texture.
