Biscuit Cake Slice

My mum got this recipe from a friend years ago, after we went to a party at her house and everybody was raving about this slice!! It is super easy to make and you don't need to use your oven :-)
The recipe can be doubled, which I usually do!

1/2 tin sweetened condensed milk
2T cocoa
125g butter
250g plain biscuits (eg. malt, round wine)

Melt butter, condensed milk and cocoa in a saucepan. Mix with the crushed biscuits. Press into a slice tin and ice with chocolate icing. Set in the refrigerator.