Line a 20cm springform tin with baking parchment
Crush 250g digestive biscuits to fine crumbs and mix with 100g melted unsalted butter
Press the biscuit mixture evenly into the base of the tin and chill in the fridge
Beat 500g full-fat cream cheese with 150g caster sugar until smooth
Stir in the zest of 2 large lemons and 90ml lemon juice until combined
Whip 300ml double cream to soft peaks
Gently fold the whipped cream into the cream cheese mixture until smooth
Spoon the filling over the chilled base and smooth the top
Chill in the fridge for at least 4–6 hours or overnight
Run a knife around the tin, remove the cheesecake, slice, and serve