1.
In large bowl, whip the cream until stiff peaks form; a cool bowl and cool beaters are said to help this process.
2.
Fold in the condensed milk and the vanilla.
3.
Fold in your crushed chocolate.
4.
Layer some biscuits, face down, at the bottom of a baking dish or on a cookie sheet (make sure the container fits in your freezer).
5.
Using either a spoon or a piping bag, scoop or pipe some of the creamy mixture onto the biscuits, how thick you want it is up to you. If using a piping bag, make sure the opening is large enough for the crumbled chocolate to fit through.
6.
Place biscuits face up onto the cream (try to align the biscuits).
7.
Cover with a piece of baking paper, and start again with a new layer of sandwiches, starting with face down biscuits (as above).
8.
Build up as many layers of sandwiches as you can/want using baking paper between each layer. The baking paper is not essential but makes separating the sandwiches a little bit easier.
9.
The thickness of your creamy mixture will determine how many biscuits you will actually need.
10.
Place in the freezer until frozen (this can take anywhere from 2 to 8 hours).
11.
When sandwiches are frozen, wrap in plastic wrap or in a freezer proof container.