In a bowl, mix the crushed digestive biscuits with melted butter until well combined.
Press the biscuit mixture firmly into the base of a 20cm springform cake tin. Chill in the fridge while preparing the filling.
In another bowl, beat the cream cheese until smooth.
In a separate bowl, whip the double cream until it forms soft peaks.
Gradually add the icing sugar to the cream cheese, followed by the vanilla extract and lemon zest, mixing well after each addition.
Gently fold the whipped cream into the cream cheese mixture until fully combined.
Pour the filling over the chilled biscuit base and smooth the top with a spatula.
Cover the tin with cling film and refrigerate for at least 4 hours or until set.
Once set, remove the cheesecake from the tin and transfer to a serving plate.
Top with sliced strawberries if desired, and serve chilled.
