Method

• Stir together the digestive biscuits, soft brown sugar and melted butter. Empty into a 23cm springform cake tin and press out level. Leave to chill in the fridge while you make the base. (Use a smaller tin if you want a thicker base.)
• Mix together, really well, (make plenty of for this part) the mascarpone cheese, cream, condensed milk and lemon zest. Slowly add the lemon juice to the mix a wee bit at a time. Use an electric mixer if you have one. Spend about 10 minutes mixing these ingredients together. The longer you mix, the thicker the topping gets in the bowl.
• Pour onto your chilled base, then return to the fridge for a few hours for it to set.