Prepare the Blueberry Compote: Place the blueberries, 60g of caster sugar, and lemon juice in a small saucepan over medium heat. Stir gently as the berries begin to soften and release their juices—you’ll hear a gentle popping sound as the skins burst, and the liquid will turn a deep, royal purple. Once the mixture is bubbling, cook for 5 minutes until it has thickened slightly. Stir in the cornflour slurry and cook for another 30 seconds, until the compote coats the back of a spoon and looks glossy. Remove from the heat and allow it to cool completely to room temperature. It will thicken further as it cools.

Make the Biscuit Base: Place the digestive biscuits in a sealed plastic bag and crush them with a rolling pin until you have fine crumbs with a few small pebbles for texture—the mixture should look like wet sand when you’re done. Alternatively, pulse them in a food processor. Transfer the crumbs to a mixing bowl, pour in the melted butter, the 1 tablespoon of caster sugar, and the salt. Stir with a fork until every crumb is coated and the mixture clumps together when pressed between your fingers. The aroma of warm butter and biscuit is deeply comforting at this stage.

Press the Base: Line a 20cm x 20cm square baking tin with baking parchment, leaving an overhang on two opposite sides to act as handles. Tip the crumb mixture into the tin and press it down firmly and evenly using the flat bottom of a measuring cup or a glass. The surface should be smooth and compacted, with no loose crumbs. Place the tin in the refrigerator to chill while you prepare the filling—this gives the butter a chance to set, preventing the base from crumbling when you cut the bars.

Whip the Cream Cheese Filling: In a large bowl, beat the room-temperature cream cheese with the 150g of caster sugar and the vanilla bean paste using an electric hand mixer. Beat on medium speed for 2-3 minutes until the mixture is completely smooth, pale, and fluffy—there should be no lumps whatsoever. The texture will be thick and velvety. If using, fold in the lemon zest at this point.

Fold in the Whipped Cream: In a separate clean bowl, whip the cold double cream until it holds stiff peaks—this takes about 3-4 minutes with an electric mixer. You’ll know it’s ready when you lift the beaters and the cream stands up in firm, unmoving peaks. The sound will change from a sloshing to a soft, dense thud. Take a large spoonful of the whipped cream and stir it into the cream cheese mixture to loosen it, then gently fold in the remaining whipped cream using a spatula. Fold until no white streaks remain; the final mixture should be airy, mousse-like, and very pale.

Assemble the Layers: Remove the chilled tin from the fridge. Spoon half of the cheesecake filling onto the base and spread it into an even layer using an offset spatula. Drop small spoonfuls of the cooled blueberry compote (about half of it) over the filling, then drag a knife through the compote to create a marbled swirl effect. Repeat with the remaining filling, spreading it gently on top, then add the rest of the compote and swirl again. The top should look like an abstract painting—ribbons of deep purple against a creamy white canvas.

Chill and Set: Gently tap the tin on the countertop to release any air bubbles. Cover the tin loosely with cling film and refrigerate for a minimum of 4 hours, but ideally 8 hours or overnight. The filling should feel firm to the touch and no longer jiggly when you gently shake the tin. The longer it sets, the cleaner your slices will be.

Slice and Serve: Using the parchment overhang, lift the entire cheesecake block out of the tin and place it on a cutting board. For the cleanest slices, use a large, sharp chef’s knife and wipe it clean with a damp, hot cloth between each cut. Trim the edges first to reveal the pristine layers, then slice into 12 equal bars. Arrange each bar on a serving plate with a small dollop of extra compote, a few fresh blueberries, and a tiny mint sprig. This small touch makes all the difference when presenting to guests.