Crush the digestive biscuits into fine crumbs using a food processor or by placing them in a sealed bag and crushing with a rolling pin. Mix the crumbs thoroughly with melted butter until well combined and the mixture resembles wet sand.

Press the biscuit mixture firmly into the base of a 23cm springform tin, using the back of a spoon or bottom of a glass to create an even, compact layer. Refrigerate for at least 30 minutes to set.

In a large bowl, beat the softened cream cheese and caster sugar together until completely smooth and creamy with no visible sugar granules, about 2-3 minutes.

Gradually whisk in the double cream until the mixture is thick, holds soft peaks, and looks luxuriously smooth. This takes about 2-3 minutes with an electric mixer.

Gently fold in the orange zest and orange extract until evenly distributed throughout the filling, being careful not to overmix and deflate the mixture.

Pour the cream cheese mixture over the chilled biscuit base and spread evenly with a spatula. Tap the tin gently on the counter a few times to release any air bubbles.

Drizzle the melted dark chocolate over the top in your desired pattern - swirls, zigzags, or a simple drizzle all look beautiful.

Cover the cheesecake with cling film and refrigerate for at least 4 hours, or preferably overnight, to allow it to set completely and the flavors to meld.

Before serving, run a knife around the edge of the springform tin and carefully release the sides. Transfer to a serving plate and garnish with extra orange zest or chocolate shavings if desired.