Method

​1 Grease and line an 18cm (7 inch) loose bottom tin before you get going.

2 To make the base: pop the biscuits in a plastic bag and crush finely with a rolling pin. Once the biscuits are crushed into breadcrumbs, add the melted butter and mix well. Press the crumbs firmly into the base of the prepared tin and chill for 2 hours to set.

3 When you're ready to make the filling, preheat the oven to 160°C/fan 140°C/gas mark 3. Start by beating the egg yolks until pale and thick in a bowl. Beat in the condensed milk and add the zest of 3 limes and the juice of 6. The mixture will suddenly thicken due to the acidity of the lime juice.

4 Pour the mixture on to the biscuit base and cook for 15 minutes or until lightly set. Put it to one-side to cool before chilling it for 1–2 hours. It is now ready to serve! Just finish with by whipping up the cream and spread it on top, and decorate with a little more lime zest for good measure.