Here you go Li, really is easy peasy and delicious too.
This recipe is from Nigella Lawson's 'How To Be A Domestic Goddess' if anyone has the book it's on page 103. This is the quick and easy way, you can also do a baked version but this one doesn't need cooking.
For the base -
200g digestive biscuits
The recipe says 50g of softened butter but I add more like 70 to 80g as it stays together much better
Simply add the biscuits (broken up a bit first) and the softened butter to a food mixer and blitz until you get crumbs, press down into a springform tin (approx 23cm) and leave to chill in the fridge.
For the filling -
Juice and zest of 4 limes
397g can of condensed milk
300ml double cream
Electrically whisk all the ingredients together until thick and creamy, add to the base and leave to set in the fridge for at least half an hour.
and that's it, a very easy pudding!!.