Brush the bottom of a 23cm/9in springform cake tin with some of the melted butter and place a round of greaseproof paper in the base.
Crush the biscuits and tip them into a bowl, add the melted butter and honey and stir until well combined.
Tip the mixture into the bottom of the cake tin. Using the back of a spoon, gently push the crumbs from the centre outward, until smooth and level. This will form the base of the cheesecake. Chill in the fridge while making the filling.
For the filling, mix the mascarpone cheese, lemon juice and zest, caster sugar and icing sugar together in a bowl until well combined. Do not mix the mixture too much as this will cause it to split. Taste the mixture and add more sugar, to taste.
Spoon the mixture into the tin on top of the chilled biscuit mixture and chill in the fridge for at least 2 hours.
When ready to serve, either run a hot cloth or blowtorch round the outside of the tin and ease out the cheesecake.
For the sauce, blend most of the fruits with some icing sugar (to taste) in a food processor until smooth. Pass the sauce through a sieve.
Place the cheesecake onto a plate, decorate the top with the sprigs of fresh mint and spoon the sauce around the side. Decorate with the remaining berries.