Prepare the crust: Tip the digestive biscuits into a sturdy food bag and crush them with a rolling pin until you have fine crumbs that look like wet sand. Mix the crumbs with the melted butter and 2 tablespoons of caster sugar until every grain feels damp and holds together when pinched. Press the mixture firmly into the base of a 23cm springform tin — use the bottom of a glass to get an even, compact layer. You'll hear a satisfying crunch as it compresses.

Chill the base: Pop the tin into the fridge for at least 30 minutes. The butter will set, and the crust will feel firm and solid to the touch when you gently press the edge.

Start the filling: In a large mixing bowl, beat the cream cheese with the 150g caster sugar using an electric mixer. Work until the mixture looks pale, fluffy, and completely free of lumps — this should take about 3 minutes. The texture should feel light and airy, almost like a cloud.

Add the lemon: Pour in the lemon juice, lemon zest, and vanilla extract. Mix on a low speed until everything is combined. You'll smell the bright, sharp aroma of fresh citrus cutting through the sweetness.

Whip the cream: In a separate bowl, whip the 200ml of double cream until it holds soft peaks. When you lift the whisk, the cream should flop over gently rather than standing stiff. The sound of the whisk against the bowl will change from a splash to a soft, muffled thud as the cream thickens.

Fold together: Gently fold the whipped cream into the lemon and cream cheese mixture. Use a spatula and a light hand — cut through the centre, scrape along the bottom, and turn the bowl. Stop as soon as you see no more white streaks. The filling should look glossy, thick, and uniform in colour.

Assemble the cheesecake: Spoon the filling onto the chilled crust and spread it evenly. Give the tin a gentle tap on the worktop to release any hidden air bubbles. The surface will look smooth and slightly wobbly.

Chill thoroughly: Cover the tin with cling film and refrigerate for at least 6 hours, though overnight is far better. The filling will set into a firm, sliceable texture that feels clean and creamy against the tongue.

Add the topping (optional): Whip the remaining 300ml double cream with the icing sugar until it holds stiff peaks. Spread or pipe it over the set cheesecake. Finish with extra lemon zest or thin slices of lemon for a pretty, professional touch.