Powder the biscuits by crushing them between two sheets of butter paper with a rolling pin or in a mixie.
Heat the butter to melt, add the biscuits and mix well.
Shut off the heat and add the sugar.
Line the base and sides of the serving dish evenly and smoothly with the biscuit mixture, put aside to cool.
In another bowl, whip the cream, add the condensed milk and beat the mixture while pouring in the lemon juice.
Now add the lemon rind and mix again.
Pour the mixture into the cooled biscuit shell and chill for 6-8 hours or till set.
Chilling it overnight is ideal.
Garnish with a slice of lemon and serve.